WEBVTT Kind: captions Language: en 00:00:00.550 --> 00:00:12.390 align:start position:0% [Music] 00:00:12.390 --> 00:00:12.400 align:start position:0% 00:00:12.400 --> 00:00:17.510 align:start position:0% okay<00:00:13.360> uh<00:00:14.360> hello<00:00:14.679> again<00:00:15.199> everybody 00:00:17.510 --> 00:00:17.520 align:start position:0% okay uh hello again everybody 00:00:17.520 --> 00:00:22.109 align:start position:0% okay uh hello again everybody hello<00:00:18.520> welcome<00:00:18.800> to<00:00:19.039> day<00:00:19.240> two<00:00:19.920> all<00:00:20.439> devor 00:00:22.109 --> 00:00:22.119 align:start position:0% hello welcome to day two all devor 00:00:22.119 --> 00:00:26.550 align:start position:0% hello welcome to day two all devor zero<00:00:23.119> uh<00:00:23.240> I'm<00:00:23.320> going<00:00:23.439> to<00:00:23.560> start<00:00:23.880> by<00:00:24.760> um<00:00:25.599> talking 00:00:26.550 --> 00:00:26.560 align:start position:0% zero uh I'm going to start by um talking 00:00:26.560 --> 00:00:28.269 align:start position:0% zero uh I'm going to start by um talking a<00:00:26.720> little<00:00:26.960> bit<00:00:27.240> about 00:00:28.269 --> 00:00:28.279 align:start position:0% a little bit about 00:00:28.279 --> 00:00:30.749 align:start position:0% a little bit about solidity<00:00:29.279> the<00:00:29.640> uh 00:00:30.749 --> 00:00:30.759 align:start position:0% solidity the uh 00:00:30.759 --> 00:00:32.790 align:start position:0% solidity the uh new<00:00:31.039> contract 00:00:32.790 --> 00:00:32.800 align:start position:0% new contract 00:00:32.800 --> 00:00:34.549 align:start position:0% new contract language<00:00:33.800> and 00:00:34.549 --> 00:00:34.559 align:start position:0% language and 00:00:34.559 --> 00:00:38.190 align:start position:0% language and then<00:00:35.559> Christian<00:00:36.520> where's<00:00:37.200> Christian 00:00:38.190 --> 00:00:38.200 align:start position:0% then Christian where's Christian 00:00:38.200 --> 00:00:41.389 align:start position:0% then Christian where's Christian Christian<00:00:38.640> is<00:00:38.760> going<00:00:38.920> to<00:00:39.239> continue<00:00:39.800> with<00:00:40.399> uh 00:00:41.389 --> 00:00:41.399 align:start position:0% Christian is going to continue with uh 00:00:41.399 --> 00:00:43.310 align:start position:0% Christian is going to continue with uh uh<00:00:42.000> the<00:00:42.120> implementation<00:00:42.760> and<00:00:42.879> a<00:00:43.000> lot<00:00:43.120> more 00:00:43.310 --> 00:00:43.320 align:start position:0% uh the implementation and a lot more 00:00:43.320 --> 00:00:45.389 align:start position:0% uh the implementation and a lot more sort<00:00:43.480> of<00:00:43.600> details<00:00:43.960> and<00:00:44.120> road<00:00:44.399> map<00:00:45.120> of<00:00:45.280> the 00:00:45.389 --> 00:00:45.399 align:start position:0% sort of details and road map of the 00:00:45.399 --> 00:00:47.670 align:start position:0% sort of details and road map of the future<00:00:45.680> of 00:00:47.670 --> 00:00:47.680 align:start position:0% future of 00:00:47.680 --> 00:00:50.110 align:start position:0% future of it<00:00:48.680> so<00:00:48.879> I'm<00:00:49.039> just<00:00:49.199> going 00:00:50.110 --> 00:00:50.120 align:start position:0% it so I'm just going 00:00:50.120 --> 00:00:54.430 align:start position:0% it so I'm just going to<00:00:51.120> basically<00:00:51.559> go<00:00:51.760> into<00:00:52.640> what<00:00:53.160> drove<00:00:53.879> the 00:00:54.430 --> 00:00:54.440 align:start position:0% to basically go into what drove the 00:00:54.440 --> 00:00:58.270 align:start position:0% to basically go into what drove the original<00:00:55.440> um<00:00:55.879> sort<00:00:56.079> of<00:00:56.640> need<00:00:57.000> for 00:00:58.270 --> 00:00:58.280 align:start position:0% original um sort of need for 00:00:58.280 --> 00:01:04.030 align:start position:0% original um sort of need for a<00:00:59.280> new<00:00:59.519> language 00:01:04.030 --> 00:01:04.040 align:start position:0% 00:01:04.040 --> 00:01:06.469 align:start position:0% so<00:01:04.239> our<00:01:04.400> main<00:01:04.640> issue<00:01:04.960> is<00:01:05.320> that<00:01:05.519> we<00:01:05.680> need<00:01:06.000> people 00:01:06.469 --> 00:01:06.479 align:start position:0% so our main issue is that we need people 00:01:06.479 --> 00:01:10.550 align:start position:0% so our main issue is that we need people lots<00:01:06.680> of<00:01:06.880> people<00:01:07.280> to<00:01:07.479> write<00:01:07.960> contracts<00:01:08.920> and 00:01:10.550 --> 00:01:10.560 align:start position:0% lots of people to write contracts and 00:01:10.560 --> 00:01:14.749 align:start position:0% lots of people to write contracts and as<00:01:11.560> as<00:01:11.840> a<00:01:12.040> lot<00:01:12.720> as<00:01:12.920> often<00:01:13.200> it<00:01:13.360> is<00:01:13.520> brought<00:01:13.840> up<00:01:14.640> uh 00:01:14.749 --> 00:01:14.759 align:start position:0% as as a lot as often it is brought up uh 00:01:14.759 --> 00:01:16.230 align:start position:0% as as a lot as often it is brought up uh these<00:01:15.000> contracts<00:01:15.439> need<00:01:15.560> to<00:01:15.680> be<00:01:15.799> correct 00:01:16.230 --> 00:01:16.240 align:start position:0% these contracts need to be correct 00:01:16.240 --> 00:01:17.550 align:start position:0% these contracts need to be correct because<00:01:16.439> once<00:01:16.600> they're<00:01:16.759> on<00:01:16.840> the<00:01:16.960> blockchain 00:01:17.550 --> 00:01:17.560 align:start position:0% because once they're on the blockchain 00:01:17.560 --> 00:01:18.990 align:start position:0% because once they're on the blockchain you<00:01:17.680> can't<00:01:17.920> change<00:01:18.240> them<00:01:18.439> unless<00:01:18.680> you've<00:01:18.840> got 00:01:18.990 --> 00:01:19.000 align:start position:0% you can't change them unless you've got 00:01:19.000 --> 00:01:20.429 align:start position:0% you can't change them unless you've got some<00:01:19.119> sort<00:01:19.280> of<00:01:19.360> update<00:01:19.640> mechanism<00:01:20.040> in<00:01:20.200> place 00:01:20.429 --> 00:01:20.439 align:start position:0% some sort of update mechanism in place 00:01:20.439 --> 00:01:22.190 align:start position:0% some sort of update mechanism in place but<00:01:20.560> that<00:01:20.680> brings<00:01:20.960> along<00:01:21.520> a<00:01:21.640> whole<00:01:21.759> slew<00:01:22.079> of 00:01:22.190 --> 00:01:22.200 align:start position:0% but that brings along a whole slew of 00:01:22.200 --> 00:01:23.670 align:start position:0% but that brings along a whole slew of other<00:01:22.439> questions<00:01:22.880> like<00:01:23.040> how<00:01:23.159> do<00:01:23.280> you<00:01:23.400> trust 00:01:23.670 --> 00:01:23.680 align:start position:0% other questions like how do you trust 00:01:23.680 --> 00:01:26.870 align:start position:0% other questions like how do you trust that<00:01:23.840> the<00:01:23.960> updates<00:01:24.280> are<00:01:24.400> going<00:01:24.479> to<00:01:24.600> be<00:01:25.439> U 00:01:26.870 --> 00:01:26.880 align:start position:0% that the updates are going to be U 00:01:26.880 --> 00:01:30.190 align:start position:0% that the updates are going to be U legitimate<00:01:27.880> so<00:01:28.640> these<00:01:28.759> are<00:01:29.000> the<00:01:29.520> two<00:01:29.960> main 00:01:30.190 --> 00:01:30.200 align:start position:0% legitimate so these are the two main 00:01:30.200 --> 00:01:32.270 align:start position:0% legitimate so these are the two main things<00:01:30.560> that<00:01:30.840> that<00:01:30.920> we're<00:01:31.119> concerned<00:01:31.560> with 00:01:32.270 --> 00:01:32.280 align:start position:0% things that that we're concerned with 00:01:32.280 --> 00:01:33.830 align:start position:0% things that that we're concerned with lots<00:01:32.520> of<00:01:32.680> people<00:01:33.040> are<00:01:33.200> able<00:01:33.439> to<00:01:33.600> write 00:01:33.830 --> 00:01:33.840 align:start position:0% lots of people are able to write 00:01:33.840 --> 00:01:40.510 align:start position:0% lots of people are able to write contracts<00:01:34.720> and<00:01:35.079> that<00:01:35.240> these<00:01:35.479> contracts<00:01:36.159> are 00:01:40.510 --> 00:01:40.520 align:start position:0% 00:01:40.520 --> 00:01:44.510 align:start position:0% correct<00:01:41.520> so<00:01:42.200> one<00:01:42.320> of<00:01:42.479> the<00:01:42.720> obvious<00:01:43.119> ways<00:01:43.960> of 00:01:44.510 --> 00:01:44.520 align:start position:0% correct so one of the obvious ways of 00:01:44.520 --> 00:01:46.350 align:start position:0% correct so one of the obvious ways of getting<00:01:44.840> more<00:01:45.119> people<00:01:45.360> to<00:01:45.520> write<00:01:45.719> contracts 00:01:46.350 --> 00:01:46.360 align:start position:0% getting more people to write contracts 00:01:46.360 --> 00:01:48.510 align:start position:0% getting more people to write contracts is<00:01:46.520> to<00:01:47.320> allow<00:01:47.640> them<00:01:47.759> to<00:01:47.920> write<00:01:48.119> it<00:01:48.240> in<00:01:48.360> a 00:01:48.510 --> 00:01:48.520 align:start position:0% is to allow them to write it in a 00:01:48.520 --> 00:01:50.870 align:start position:0% is to allow them to write it in a language<00:01:49.000> that<00:01:49.119> they're<00:01:49.560> already<00:01:50.240> reasonably 00:01:50.870 --> 00:01:50.880 align:start position:0% language that they're already reasonably 00:01:50.880 --> 00:01:55.950 align:start position:0% language that they're already reasonably familiar<00:01:51.360> with<00:01:52.079> so<00:01:53.040> um<00:01:54.040> since<00:01:54.600> a<00:01:54.719> lot<00:01:54.880> of<00:01:55.079> our 00:01:55.950 --> 00:01:55.960 align:start position:0% familiar with so um since a lot of our 00:01:55.960 --> 00:01:57.950 align:start position:0% familiar with so um since a lot of our uh<00:01:56.159> prospective<00:01:56.799> developers<00:01:57.520> are<00:01:57.680> going<00:01:57.799> to 00:01:57.950 --> 00:01:57.960 align:start position:0% uh prospective developers are going to 00:01:57.960 --> 00:02:00.389 align:start position:0% uh prospective developers are going to be<00:01:58.640> people<00:01:59.000> who<00:01:59.320> who<00:01:59.439> are<00:01:59.520> already<00:02:00.200> understand 00:02:00.389 --> 00:02:00.399 align:start position:0% be people who who are already understand 00:02:00.399 --> 00:02:03.230 align:start position:0% be people who who are already understand web<00:02:00.640> Technologies<00:02:01.640> HTML<00:02:02.159> JavaScript 00:02:03.230 --> 00:02:03.240 align:start position:0% web Technologies HTML JavaScript 00:02:03.240 --> 00:02:06.630 align:start position:0% web Technologies HTML JavaScript CSS<00:02:04.240> um<00:02:04.439> it<00:02:04.560> makes<00:02:04.840> some<00:02:05.079> sense<00:02:05.759> to<00:02:06.000> have<00:02:06.280> the 00:02:06.630 --> 00:02:06.640 align:start position:0% CSS um it makes some sense to have the 00:02:06.640 --> 00:02:09.389 align:start position:0% CSS um it makes some sense to have the contract<00:02:07.360> language<00:02:08.039> be<00:02:08.640> syntactically 00:02:09.389 --> 00:02:09.399 align:start position:0% contract language be syntactically 00:02:09.399 --> 00:02:13.229 align:start position:0% contract language be syntactically similar<00:02:10.200> to<00:02:11.200> one<00:02:11.319> of<00:02:11.480> these<00:02:11.680> so 00:02:13.229 --> 00:02:13.239 align:start position:0% similar to one of these so 00:02:13.239 --> 00:02:15.270 align:start position:0% similar to one of these so JavaScript 00:02:15.270 --> 00:02:15.280 align:start position:0% JavaScript 00:02:15.280 --> 00:02:18.589 align:start position:0% JavaScript um<00:02:16.280> leverage<00:02:17.160> the<00:02:17.360> existing<00:02:17.720> skill<00:02:18.080> set<00:02:18.440> as 00:02:18.589 --> 00:02:18.599 align:start position:0% um leverage the existing skill set as 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position:0% express easily so<00:02:30.200> it<00:02:30.319> makes<00:02:30.599> sense<00:02:30.920> to<00:02:31.120> build<00:02:31.400> in<00:02:31.959> the 00:02:32.110 --> 00:02:32.120 align:start position:0% so it makes sense to build in the 00:02:32.120 --> 00:02:33.509 align:start position:0% so it makes sense to build in the concepts<00:02:32.599> that<00:02:32.680> we<00:02:32.800> know<00:02:33.000> we're<00:02:33.160> going<00:02:33.319> to 00:02:33.509 --> 00:02:33.519 align:start position:0% concepts that we know we're going to 00:02:33.519 --> 00:02:35.750 align:start position:0% concepts that we know we're going to need<00:02:33.760> to<00:02:34.000> use 00:02:35.750 --> 00:02:35.760 align:start position:0% need to use 00:02:35.760 --> 00:02:38.910 align:start position:0% need to use often 00:02:38.910 --> 00:02:38.920 align:start position:0% 00:02:38.920 --> 00:02:42.990 align:start position:0% um<00:02:39.920> a<00:02:40.159> contract<00:02:40.840> language<00:02:41.840> it<00:02:42.000> makes<00:02:42.400> sense<00:02:42.800> to 00:02:42.990 --> 00:02:43.000 align:start position:0% um a contract language it makes sense to 00:02:43.000 --> 00:02:45.869 align:start position:0% um a contract language it makes sense to have<00:02:43.239> contracts<00:02:43.920> as<00:02:44.040> a<00:02:44.239> first<00:02:44.720> class<00:02:45.040> citizen 00:02:45.869 --> 00:02:45.879 align:start position:0% have contracts as a first class citizen 00:02:45.879 --> 00:02:47.070 align:start position:0% have contracts as a first class citizen in<00:02:46.080> that 00:02:47.070 --> 00:02:47.080 align:start position:0% in that 00:02:47.080 --> 00:02:49.350 align:start position:0% in that language<00:02:48.080> so<00:02:48.280> what<00:02:48.400> we<00:02:48.519> do<00:02:48.720> is<00:02:48.879> we<00:02:49.040> take<00:02:49.239> the 00:02:49.350 --> 00:02:49.360 align:start position:0% language so what we do is we take the 00:02:49.360 --> 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think about it 00:02:57.959 --> 00:02:59.949 align:start position:0% programming and if you think about it contracts<00:02:58.480> can<00:02:58.760> very<00:02:58.959> easily<00:02:59.280> be<00:02:59.480> con 00:02:59.949 --> 00:02:59.959 align:start position:0% contracts can very easily be con 00:02:59.959 --> 00:03:02.190 align:start position:0% contracts can very easily be con considered<00:03:00.640> classes<00:03:01.080> or<00:03:01.440> objects<00:03:01.879> depending 00:03:02.190 --> 00:03:02.200 align:start position:0% considered classes or objects depending 00:03:02.200 --> 00:03:05.630 align:start position:0% considered classes or objects depending on<00:03:03.040> um<00:03:03.920> whether<00:03:04.120> you<00:03:04.280> look<00:03:04.480> upon<00:03:04.799> the<00:03:05.480> the 00:03:05.630 --> 00:03:05.640 align:start position:0% on um whether you look upon the the 00:03:05.640 --> 00:03:07.509 align:start position:0% on um whether you look upon the the instance<00:03:06.040> of<00:03:06.159> the<00:03:06.280> contract<00:03:06.640> or<00:03:06.760> the<00:03:06.920> contract 00:03:07.509 --> 00:03:07.519 align:start position:0% instance of the contract or the contract 00:03:07.519 --> 00:03:09.670 align:start position:0% instance of the contract or the contract the<00:03:07.720> the<00:03:08.000> Prototype<00:03:08.440> of<00:03:08.519> the 00:03:09.670 --> 00:03:09.680 align:start position:0% the the Prototype of the 00:03:09.680 --> 00:03:12.430 align:start position:0% the the Prototype of the contract<00:03:10.680> and<00:03:10.799> so<00:03:11.080> we<00:03:11.360> we<00:03:11.879> uh<00:03:12.000> base<00:03:12.280> the 00:03:12.430 --> 00:03:12.440 align:start position:0% contract and so we we uh base the 00:03:12.440 --> 00:03:13.990 align:start position:0% contract and so we we uh base the language<00:03:12.760> around<00:03:13.040> this 00:03:13.990 --> 00:03:14.000 align:start position:0% language around this 00:03:14.000 --> 00:03:17.190 align:start position:0% language around this notion<00:03:15.000> similarly<00:03:15.560> within<00:03:16.200> ethereum 00:03:17.190 --> 00:03:17.200 align:start position:0% notion similarly within ethereum 00:03:17.200 --> 00:03:20.149 align:start position:0% notion similarly within ethereum contracts<00:03:17.640> have<00:03:17.879> storage<00:03:18.879> now<00:03:19.760> having<00:03:19.959> to 00:03:20.149 --> 00:03:20.159 align:start position:0% contracts have storage now having to 00:03:20.159 --> 00:03:23.070 align:start position:0% contracts have storage now having to store<00:03:20.560> things<00:03:20.840> in<00:03:21.000> terms<00:03:21.360> of<00:03:22.360> literals<00:03:22.920> is 00:03:23.070 --> 00:03:23.080 align:start position:0% store things in terms of literals is 00:03:23.080 --> 00:03:25.509 align:start position:0% store things in terms of literals is almost<00:03:23.440> like<00:03:23.959> you<00:03:24.080> know<00:03:24.280> having<00:03:24.560> a<00:03:25.200> a 00:03:25.509 --> 00:03:25.519 align:start position:0% almost like you know having a a 00:03:25.519 --> 00:03:27.190 align:start position:0% almost like you know having a a beautiful<00:03:26.080> high<00:03:26.280> level<00:03:26.519> language<00:03:26.840> and<00:03:27.000> having 00:03:27.190 --> 00:03:27.200 align:start position:0% beautiful high level language and having 00:03:27.200 --> 00:03:30.110 align:start position:0% beautiful high level language and having to<00:03:27.599> store<00:03:28.000> your<00:03:28.319> integers<00:03:28.799> as<00:03:29.000> bites<00:03:30.000> it 00:03:30.110 --> 00:03:30.120 align:start position:0% to store your integers as bites it 00:03:30.120 --> 00:03:32.390 align:start position:0% to store your integers as bites it doesn't<00:03:30.360> really<00:03:30.560> make<00:03:30.760> sense<00:03:31.040> so<00:03:31.920> what<00:03:32.080> we<00:03:32.200> do 00:03:32.390 --> 00:03:32.400 align:start position:0% doesn't really make sense so what we do 00:03:32.400 --> 00:03:33.750 align:start position:0% doesn't really make sense so what we do is<00:03:32.519> we<00:03:32.640> say<00:03:32.920> right<00:03:33.120> well<00:03:33.280> we<00:03:33.360> are<00:03:33.480> going<00:03:33.560> to 00:03:33.750 --> 00:03:33.760 align:start position:0% is we say right well we are going to 00:03:33.760 --> 00:03:35.750 align:start position:0% is we say right well we are going to support<00:03:34.480> the<00:03:34.640> storage<00:03:35.280> but<00:03:35.400> we're<00:03:35.519> going<00:03:35.599> to 00:03:35.750 --> 00:03:35.760 align:start position:0% support the storage but we're going to 00:03:35.760 --> 00:03:38.309 align:start position:0% support the storage but we're going to do<00:03:35.879> so<00:03:36.120> in<00:03:36.280> a<00:03:36.519> with<00:03:36.640> an<00:03:36.879> abstraction<00:03:37.400> layer<00:03:38.120> and 00:03:38.309 --> 00:03:38.319 align:start position:0% do so in a with an abstraction layer and 00:03:38.319 --> 00:03:39.869 align:start position:0% do so in a with an abstraction layer and actually<00:03:38.640> what<00:03:38.760> the<00:03:38.879> programmer<00:03:39.280> sees<00:03:39.640> is 00:03:39.869 --> 00:03:39.879 align:start position:0% actually what the programmer sees is 00:03:39.879 --> 00:03:42.710 align:start position:0% actually what the programmer sees is just<00:03:40.400> what<00:03:40.519> they<00:03:40.680> used<00:03:40.959> to<00:03:41.400> which<00:03:41.560> is<00:03:41.720> to<00:03:41.879> say 00:03:42.710 --> 00:03:42.720 align:start position:0% just what they used to which is to say 00:03:42.720 --> 00:03:47.270 align:start position:0% just what they used to which is to say uh<00:03:42.920> usable<00:03:43.959> types<00:03:44.959> strings<00:03:46.280> structures 00:03:47.270 --> 00:03:47.280 align:start position:0% uh usable types strings structures 00:03:47.280 --> 00:03:50.789 align:start position:0% uh usable types strings structures integers<00:03:47.760> of<00:03:47.920> various<00:03:48.280> sizes 00:03:50.789 --> 00:03:50.799 align:start position:0% integers of various sizes 00:03:50.799 --> 00:03:54.429 align:start position:0% integers of various sizes booleans<00:03:51.799> and<00:03:51.959> then<00:03:52.200> finally<00:03:53.159> contracts<00:03:53.760> do 00:03:54.429 --> 00:03:54.439 align:start position:0% booleans and then finally contracts do 00:03:54.439 --> 00:03:56.350 align:start position:0% booleans and then finally contracts do um<00:03:54.599> a<00:03:54.720> lot<00:03:54.879> of<00:03:55.079> IO<00:03:55.400> and<00:03:55.519> whereas<00:03:55.760> in<00:03:55.920> normal 00:03:56.350 --> 00:03:56.360 align:start position:0% um a lot of IO and whereas in normal 00:03:56.360 --> 00:03:59.030 align:start position:0% um a lot of IO and whereas in normal objectoriented<00:03:57.079> languages<00:03:58.079> um<00:03:58.280> you<00:03:58.560> may<00:03:58.799> have 00:03:59.030 --> 00:03:59.040 align:start position:0% objectoriented languages um you may have 00:03:59.040 --> 00:04:00.910 align:start position:0% objectoriented languages um you may have ways<00:03:59.280> of<00:03:59.439> passing<00:04:00.040> parameters<00:04:00.480> as<00:04:00.680> in 00:04:00.910 --> 00:04:00.920 align:start position:0% ways of passing parameters as in 00:04:00.920 --> 00:04:04.390 align:start position:0% ways of passing parameters as in parameters<00:04:01.319> and<00:04:01.480> out<00:04:02.159> parameters<00:04:03.159> um<00:04:03.599> C++<00:04:04.280> for 00:04:04.390 --> 00:04:04.400 align:start position:0% parameters and out parameters um C++ for 00:04:04.400 --> 00:04:06.149 align:start position:0% parameters and out parameters um C++ for instance<00:04:04.680> uses<00:04:05.040> pointers<00:04:05.360> or<00:04:05.519> references<00:04:06.040> to 00:04:06.149 --> 00:04:06.159 align:start position:0% instance uses pointers or references to 00:04:06.159 --> 00:04:09.509 align:start position:0% instance uses pointers or references to do<00:04:06.360> that<00:04:06.879> if<00:04:07.000> you've<00:04:07.360> got<00:04:08.360> uh<00:04:09.079> there<00:04:09.200> are<00:04:09.439> there 00:04:09.509 --> 00:04:09.519 align:start position:0% do that if you've got uh there are there 00:04:09.519 --> 00:04:12.149 align:start position:0% do that if you've got uh there are there are<00:04:10.200> language<00:04:10.560> idioms<00:04:11.000> that<00:04:11.159> allow<00:04:11.400> you<00:04:11.560> to<00:04:12.000> um 00:04:12.149 --> 00:04:12.159 align:start position:0% are language idioms that allow you to um 00:04:12.159 --> 00:04:14.429 align:start position:0% are language idioms that allow you to um have<00:04:12.360> multiple<00:04:12.840> outputs<00:04:13.680> uh<00:04:13.799> sort<00:04:14.000> of<00:04:14.120> as<00:04:14.319> part 00:04:14.429 --> 00:04:14.439 align:start position:0% have multiple outputs uh sort of as part 00:04:14.439 --> 00:04:16.310 align:start position:0% have multiple outputs uh sort of as part of<00:04:14.760> again<00:04:15.000> a<00:04:15.120> first<00:04:15.480> class<00:04:15.840> portion<00:04:16.079> of<00:04:16.160> the 00:04:16.310 --> 00:04:16.320 align:start position:0% of again a first class portion of the 00:04:16.320 --> 00:04:18.469 align:start position:0% of again a first class portion of the language<00:04:17.160> I<00:04:17.239> believe<00:04:17.560> go<00:04:17.840> is<00:04:17.959> one<00:04:18.079> of<00:04:18.239> these 00:04:18.469 --> 00:04:18.479 align:start position:0% language I believe go is one of these 00:04:18.479 --> 00:04:19.949 align:start position:0% language I believe go is one of these Jeff<00:04:18.720> will<00:04:18.919> probably<00:04:19.199> be<00:04:19.280> able<00:04:19.440> to<00:04:19.560> confirm 00:04:19.949 --> 00:04:19.959 align:start position:0% Jeff will probably be able to confirm 00:04:19.959 --> 00:04:24.030 align:start position:0% Jeff will probably be able to confirm that<00:04:20.160> wherever<00:04:20.440> he<00:04:20.919> yeah<00:04:22.000> yeah<00:04:23.000> um<00:04:23.240> and<00:04:23.400> so 00:04:24.030 --> 00:04:24.040 align:start position:0% that wherever he yeah yeah um and so 00:04:24.040 --> 00:04:25.510 align:start position:0% that wherever he yeah yeah um and so this<00:04:24.280> this<00:04:24.400> makes<00:04:24.600> a<00:04:24.680> lot<00:04:24.840> of<00:04:24.960> sense<00:04:25.199> within 00:04:25.510 --> 00:04:25.520 align:start position:0% this this makes a lot of sense within 00:04:25.520 --> 00:04:28.070 align:start position:0% this this makes a lot of sense within contracts<00:04:26.120> where<00:04:26.639> um<00:04:27.000> we<00:04:27.160> are<00:04:27.520> going<00:04:27.720> to<00:04:27.919> want 00:04:28.070 --> 00:04:28.080 align:start position:0% contracts where um we are going to want 00:04:28.080 --> 00:04:31.110 align:start position:0% contracts where um we are going to want to<00:04:28.960> call<00:04:29.280> things<00:04:29.479> in<00:04:29.800> and<00:04:29.919> then<00:04:30.280> take<00:04:30.639> data<00:04:30.960> out 00:04:31.110 --> 00:04:31.120 align:start position:0% to call things in and then take data out 00:04:31.120 --> 00:04:32.870 align:start position:0% to call things in and then take data out of<00:04:31.280> the<00:04:31.440> contract<00:04:31.960> without<00:04:32.199> having<00:04:32.400> to<00:04:32.600> worry 00:04:32.870 --> 00:04:32.880 align:start position:0% of the contract without having to worry 00:04:32.880 --> 00:04:36.749 align:start position:0% of the contract without having to worry about<00:04:33.120> things<00:04:33.320> like 00:04:36.749 --> 00:04:36.759 align:start position:0% 00:04:36.759 --> 00:04:39.189 align:start position:0% references<00:04:37.759> so<00:04:37.919> then<00:04:38.039> we<00:04:38.160> come<00:04:38.320> on<00:04:38.440> to<00:04:38.840> making 00:04:39.189 --> 00:04:39.199 align:start position:0% references so then we come on to making 00:04:39.199 --> 00:04:40.830 align:start position:0% references so then we come on to making things<00:04:39.759> you<00:04:39.880> know<00:04:40.000> how<00:04:40.120> do<00:04:40.240> we<00:04:40.400> make<00:04:40.600> things 00:04:40.830 --> 00:04:40.840 align:start position:0% things you know how do we make things 00:04:40.840 --> 00:04:42.830 align:start position:0% things you know how do we make things correct<00:04:41.120> how<00:04:41.199> do<00:04:41.320> we<00:04:41.440> make<00:04:41.560> it<00:04:41.840> most<00:04:42.280> likely 00:04:42.830 --> 00:04:42.840 align:start position:0% correct how do we make it most likely 00:04:42.840 --> 00:04:44.950 align:start position:0% correct how do we make it most likely that<00:04:43.039> these<00:04:43.280> contracts<00:04:44.199> are<00:04:44.400> going<00:04:44.600> to<00:04:44.759> be 00:04:44.950 --> 00:04:44.960 align:start position:0% that these contracts are going to be 00:04:44.960 --> 00:04:48.430 align:start position:0% that these contracts are going to be correct<00:04:46.039> well<00:04:47.039> the<00:04:47.199> most<00:04:47.520> obvious<00:04:47.919> way<00:04:48.160> is 00:04:48.430 --> 00:04:48.440 align:start position:0% correct well the most obvious way is 00:04:48.440 --> 00:04:53.510 align:start position:0% correct well the most obvious way is unit<00:04:48.800> testing<00:04:49.600> right<00:04:50.680> you<00:04:51.680> but<00:04:52.120> unit<00:04:52.520> testing 00:04:53.510 --> 00:04:53.520 align:start position:0% unit testing right you but unit testing 00:04:53.520 --> 00:04:56.230 align:start position:0% unit testing right you but unit testing at<00:04:53.680> least<00:04:54.039> with<00:04:54.680> uh<00:04:54.800> traditional<00:04:55.720> um<00:04:55.919> sort<00:04:56.120> of 00:04:56.230 --> 00:04:56.240 align:start position:0% at least with uh traditional um sort of 00:04:56.240 --> 00:04:57.629 align:start position:0% at least with uh traditional um sort of basic<00:04:56.520> unit<00:04:56.800> testing<00:04:57.039> Frameworks<00:04:57.479> are<00:04:57.560> going 00:04:57.629 --> 00:04:57.639 align:start position:0% basic unit testing Frameworks are going 00:04:57.639 --> 00:05:00.110 align:start position:0% basic unit testing Frameworks are going to<00:04:58.039> require<00:04:59.039> effort<00:04:59.440> at<00:04:59.720> least<00:04:59.880> a<00:04:59.960> small 00:05:00.110 --> 00:05:00.120 align:start position:0% to require effort at least a small 00:05:00.120 --> 00:05:01.909 align:start position:0% to require effort at least a small amount<00:05:00.320> of<00:05:00.440> effort<00:05:00.759> from<00:05:00.919> the<00:05:01.080> programmer<00:05:01.600> to 00:05:01.909 --> 00:05:01.919 align:start position:0% amount of effort from the programmer to 00:05:01.919 --> 00:05:04.310 align:start position:0% amount of effort from the programmer to to<00:05:02.280> put<00:05:02.479> the<00:05:02.600> unit<00:05:02.919> tests<00:05:03.280> in<00:05:03.720> so<00:05:03.880> what<00:05:04.000> we<00:05:04.120> do 00:05:04.310 --> 00:05:04.320 align:start position:0% to put the unit tests in so what we do 00:05:04.320 --> 00:05:06.670 align:start position:0% to put the unit tests in so what we do is<00:05:04.440> we<00:05:04.600> devise<00:05:04.960> the<00:05:05.120> language<00:05:05.919> or<00:05:06.080> at<00:05:06.199> least 00:05:06.670 --> 00:05:06.680 align:start position:0% is we devise the language or at least 00:05:06.680 --> 00:05:10.029 align:start position:0% is we devise the language or at least the<00:05:07.160> language<00:05:08.160> um<00:05:08.800> development<00:05:09.400> environment 00:05:10.029 --> 00:05:10.039 align:start position:0% the language um development environment 00:05:10.039 --> 00:05:12.270 align:start position:0% the language um development environment combination<00:05:11.039> um<00:05:11.199> to<00:05:11.360> make<00:05:11.560> unit<00:05:11.880> tests 00:05:12.270 --> 00:05:12.280 align:start position:0% combination um to make unit tests 00:05:12.280 --> 00:05:15.029 align:start position:0% combination um to make unit tests actually<00:05:12.600> easier<00:05:13.000> to<00:05:13.199> have<00:05:13.360> in<00:05:13.680> than<00:05:13.880> not<00:05:14.840> so 00:05:15.029 --> 00:05:15.039 align:start position:0% actually easier to have in than not so 00:05:15.039 --> 00:05:17.510 align:start position:0% actually easier to have in than not so we<00:05:15.160> do<00:05:15.360> things<00:05:15.720> like<00:05:16.280> all<00:05:16.600> already<00:05:17.000> have<00:05:17.320> a 00:05:17.510 --> 00:05:17.520 align:start position:0% we do things like all already have a 00:05:17.520 --> 00:05:20.070 align:start position:0% we do things like all already have a space<00:05:17.880> where<00:05:18.080> the<00:05:18.199> unit<00:05:18.520> test<00:05:18.840> goes<00:05:19.800> and<00:05:19.919> then 00:05:20.070 --> 00:05:20.080 align:start position:0% space where the unit test goes and then 00:05:20.080 --> 00:05:21.550 align:start position:0% space where the unit test goes and then the<00:05:20.199> ability<00:05:20.639> just<00:05:20.759> to<00:05:20.919> press<00:05:21.120> enter<00:05:21.360> and<00:05:21.440> you 00:05:21.550 --> 00:05:21.560 align:start position:0% the ability just to press enter and you 00:05:21.560 --> 00:05:23.189 align:start position:0% the ability just to press enter and you get<00:05:21.680> another<00:05:21.960> unit<00:05:22.240> test<00:05:22.440> so<00:05:22.600> just<00:05:22.759> make<00:05:22.919> it 00:05:23.189 --> 00:05:23.199 align:start position:0% get another unit test so just make it 00:05:23.199 --> 00:05:27.710 align:start position:0% get another unit test so just make it incredibly<00:05:24.199> easy<00:05:24.840> to<00:05:25.160> place<00:05:26.160> um<00:05:26.800> the<00:05:27.440> uh 00:05:27.710 --> 00:05:27.720 align:start position:0% incredibly easy to place um the uh 00:05:27.720 --> 00:05:29.990 align:start position:0% incredibly easy to place um the uh expected<00:05:28.280> results<00:05:28.840> or<00:05:28.960> a<00:05:29.120> set<00:05:29.280> of<00:05:29.680> expected 00:05:29.990 --> 00:05:30.000 align:start position:0% expected results or a set of expected 00:05:30.000 --> 00:05:32.150 align:start position:0% expected results or a set of expected results<00:05:30.840> um<00:05:31.000> in 00:05:32.150 --> 00:05:32.160 align:start position:0% results um in 00:05:32.160 --> 00:05:36.790 align:start position:0% results um in there<00:05:33.160> the<00:05:33.360> second<00:05:33.759> thing<00:05:35.039> that<00:05:36.039> really<00:05:36.479> helps 00:05:36.790 --> 00:05:36.800 align:start position:0% there the second thing that really helps 00:05:36.800 --> 00:05:39.990 align:start position:0% there the second thing that really helps us<00:05:37.080> guarantee<00:05:38.039> that<00:05:38.560> um<00:05:38.759> a<00:05:39.000> contract<00:05:39.680> is 00:05:39.990 --> 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anyone at all a little bit okay so<00:06:00.919> formal<00:06:01.360> proofing<00:06:01.720> is<00:06:01.800> the<00:06:01.960> notion<00:06:02.319> that 00:06:02.469 --> 00:06:02.479 align:start position:0% so formal proofing is the notion that 00:06:02.479 --> 00:06:06.150 align:start position:0% so formal proofing is the notion that you<00:06:02.639> can<00:06:03.360> um<00:06:04.240> you<00:06:04.360> can<00:06:04.600> describe<00:06:05.199> you<00:06:05.319> can 00:06:06.150 --> 00:06:06.160 align:start position:0% you can um you can describe you can 00:06:06.160 --> 00:06:11.230 align:start position:0% you can um you can describe you can specify<00:06:07.400> um<00:06:08.639> the<00:06:09.639> um<00:06:10.039> you<00:06:10.160> can<00:06:10.319> specify<00:06:10.680> some 00:06:11.230 --> 00:06:11.240 align:start position:0% specify um the um you can specify some 00:06:11.240 --> 00:06:13.990 align:start position:0% specify um the um you can specify some expectation<00:06:12.240> of<00:06:12.479> a 00:06:13.990 --> 00:06:14.000 align:start position:0% expectation of a 00:06:14.000 --> 00:06:17.629 align:start position:0% expectation of a program<00:06:15.000> and<00:06:15.160> that<00:06:15.440> this<00:06:16.400> expectation<00:06:17.400> can 00:06:17.629 --> 00:06:17.639 align:start position:0% program and that this expectation can 00:06:17.639 --> 00:06:20.950 align:start position:0% program and that this expectation can either<00:06:17.880> be<00:06:18.120> proved<00:06:18.599> or<00:06:18.800> not<00:06:19.080> proved<00:06:20.080> but<00:06:20.360> it<00:06:20.639> it 00:06:20.950 --> 00:06:20.960 align:start position:0% either be proved or not proved but it it 00:06:20.960 --> 00:06:23.350 align:start position:0% either be proved or not proved but it it that<00:06:21.199> happens<00:06:21.880> at<00:06:22.000> the<00:06:22.199> point<00:06:22.440> of<00:06:22.680> compilation 00:06:23.350 --> 00:06:23.360 align:start position:0% that happens at the point of compilation 00:06:23.360 --> 00:06:25.430 align:start position:0% that happens at the point of compilation not<00:06:23.599> at<00:06:23.759> the<00:06:23.880> point<00:06:24.080> of<00:06:24.240> running<00:06:24.639> the 00:06:25.430 --> 00:06:25.440 align:start position:0% not at the point of running the 00:06:25.440 --> 00:06:28.430 align:start position:0% not at the point of running the program<00:06:26.440> so<00:06:26.680> you<00:06:26.800> can<00:06:27.120> specify<00:06:27.639> for<00:06:27.880> instance 00:06:28.430 --> 00:06:28.440 align:start position:0% program so you can specify for instance 00:06:28.440 --> 00:06:32.189 align:start position:0% program so you can specify for instance that<00:06:28.560> you<00:06:28.840> expect<00:06:29.960> um<00:06:30.199> no<00:06:30.599> matter<00:06:31.599> what<00:06:31.919> state 00:06:32.189 --> 00:06:32.199 align:start position:0% that you expect um no matter what state 00:06:32.199 --> 00:06:33.909 align:start position:0% that you expect um no matter what state the<00:06:32.360> program<00:06:32.680> gets<00:06:32.880> into<00:06:33.199> you<00:06:33.319> can<00:06:33.560> expect 00:06:33.909 --> 00:06:33.919 align:start position:0% the program gets into you can expect 00:06:33.919 --> 00:06:36.350 align:start position:0% the program gets into you can expect that<00:06:34.199> all<00:06:34.520> the<00:06:34.680> balances<00:06:35.319> will<00:06:35.560> add<00:06:35.759> up<00:06:35.960> to<00:06:36.160> a 00:06:36.350 --> 00:06:36.360 align:start position:0% that all the balances will add up to a 00:06:36.360 --> 00:06:38.510 align:start position:0% that all the balances will add up to a particular<00:06:36.840> number<00:06:37.560> and<00:06:37.720> what<00:06:37.840> you<00:06:37.919> can<00:06:38.120> do<00:06:38.400> is 00:06:38.510 --> 00:06:38.520 align:start position:0% particular number and what you can do is 00:06:38.520 --> 00:06:41.110 align:start position:0% particular number and what you can do is if<00:06:38.680> your<00:06:38.880> program<00:06:39.199> is<00:06:39.360> written<00:06:40.120> um<00:06:40.440> using<00:06:40.759> a 00:06:41.110 --> 00:06:41.120 align:start position:0% if your program is written um using a 00:06:41.120 --> 00:06:44.189 align:start position:0% if your program is written um using a particular<00:06:42.120> um<00:06:42.440> nonch<00:06:43.000> incomplete<00:06:43.599> but<00:06:43.759> non<00:06:44.039> a 00:06:44.189 --> 00:06:44.199 align:start position:0% particular um nonch incomplete but non a 00:06:44.199 --> 00:06:45.950 align:start position:0% particular um nonch incomplete but non a particular<00:06:44.639> language<00:06:45.280> still<00:06:45.560> relatively 00:06:45.950 --> 00:06:45.960 align:start position:0% particular language still relatively 00:06:45.960 --> 00:06:49.909 align:start position:0% particular language still relatively Rich<00:06:46.319> subset<00:06:46.720> of<00:06:46.880> it<00:06:47.479> um<00:06:47.800> you<00:06:47.960> can<00:06:48.199> use<00:06:48.599> this<00:06:49.560> um 00:06:49.909 --> 00:06:49.919 align:start position:0% Rich subset of it um you can use this um 00:06:49.919 --> 00:06:51.110 align:start position:0% Rich subset of it um you can use this um well<00:06:50.000> the<00:06:50.120> compiler<00:06:50.520> can<00:06:50.680> use<00:06:50.840> this<00:06:50.960> at 00:06:51.110 --> 00:06:51.120 align:start position:0% well the compiler can use this at 00:06:51.120 --> 00:06:53.309 align:start position:0% well the compiler can use this at compile<00:06:51.520> time<00:06:51.960> in<00:06:52.080> order<00:06:52.280> to<00:06:52.599> guarantee<00:06:53.160> that 00:06:53.309 --> 00:06:53.319 align:start position:0% compile time in order to guarantee that 00:06:53.319 --> 00:06:55.710 align:start position:0% compile time in order to guarantee that that<00:06:53.560> statement<00:06:54.160> always<00:06:54.720> remains<00:06:55.080> correct 00:06:55.710 --> 00:06:55.720 align:start position:0% that statement always remains correct 00:06:55.720 --> 00:06:59.110 align:start position:0% that statement always remains correct always<00:06:56.199> no<00:06:56.400> matter<00:06:56.960> what<00:06:57.960> as<00:06:58.120> long<00:06:58.759> as<00:06:58.879> long<00:06:59.039> as 00:06:59.110 --> 00:06:59.120 align:start position:0% always no matter what as long as long as 00:06:59.120 --> 00:07:01.150 align:start position:0% always no matter what as long as long as you<00:06:59.240> own<00:06:59.759> use<00:07:00.039> the<00:07:00.319> uh<00:07:00.479> the<00:07:00.599> methods<00:07:00.960> but<00:07:01.080> of 00:07:01.150 --> 00:07:01.160 align:start position:0% you own use the uh the methods but of 00:07:01.160 --> 00:07:02.510 align:start position:0% you own use the uh the methods but of course<00:07:01.319> there's<00:07:01.520> no<00:07:01.720> other<00:07:01.840> way<00:07:01.960> in<00:07:02.080> ethereum 00:07:02.510 --> 00:07:02.520 align:start position:0% course there's no other way in ethereum 00:07:02.520 --> 00:07:04.710 align:start position:0% course there's no other way in ethereum than<00:07:02.720> to<00:07:02.840> use<00:07:03.039> the<00:07:03.160> methods<00:07:04.080> um<00:07:04.360> that<00:07:04.599> that 00:07:04.710 --> 00:07:04.720 align:start position:0% than to use the methods um that that 00:07:04.720 --> 00:07:07.629 align:start position:0% than to use the methods um that that will<00:07:05.000> always<00:07:05.479> remain 00:07:07.629 --> 00:07:07.639 align:start position:0% will always remain 00:07:07.639 --> 00:07:11.070 align:start position:0% will always remain true<00:07:08.680> um<00:07:09.680> this<00:07:09.840> is<00:07:10.039> used 00:07:11.070 --> 00:07:11.080 align:start position:0% true um this is used 00:07:11.080 --> 00:07:14.350 align:start position:0% true um this is used in<00:07:12.080> existing<00:07:12.840> I<00:07:12.960> think<00:07:13.080> it's<00:07:13.240> used<00:07:13.479> in<00:07:13.960> uh<00:07:14.240> a 00:07:14.350 --> 00:07:14.360 align:start position:0% in existing I think it's used in uh a 00:07:14.360 --> 00:07:16.309 align:start position:0% in existing I think it's used in uh a lot<00:07:14.479> of<00:07:14.599> safety<00:07:14.960> critical<00:07:15.319> environments<00:07:16.199> uh 00:07:16.309 --> 00:07:16.319 align:start position:0% lot of safety critical environments uh 00:07:16.319 --> 00:07:19.189 align:start position:0% lot of safety critical environments uh nuclear<00:07:17.039> power<00:07:17.319> plants<00:07:17.680> I<00:07:17.800> believe<00:07:18.520> use 00:07:19.189 --> 00:07:19.199 align:start position:0% nuclear power plants I believe use 00:07:19.199 --> 00:07:22.230 align:start position:0% nuclear power plants I believe use techniques<00:07:19.680> like<00:07:19.879> this<00:07:20.680> um<00:07:20.960> the<00:07:21.240> Rolls-Royce 00:07:22.230 --> 00:07:22.240 align:start position:0% techniques like this um the Rolls-Royce 00:07:22.240 --> 00:07:24.029 align:start position:0% techniques like this um the Rolls-Royce uh<00:07:22.360> the<00:07:22.479> big<00:07:22.639> engines<00:07:23.120> that<00:07:23.240> you<00:07:23.319> see<00:07:23.800> on<00:07:23.919> the 00:07:24.029 --> 00:07:24.039 align:start position:0% uh the big engines that you see on the 00:07:24.039 --> 00:07:26.990 align:start position:0% uh the big engines that you see on the side<00:07:24.199> of<00:07:24.520> airliners<00:07:25.520> the<00:07:25.960> uh<00:07:26.319> the<00:07:26.520> reverse 00:07:26.990 --> 00:07:27.000 align:start position:0% side of airliners the uh the reverse 00:07:27.000 --> 00:07:30.670 align:start position:0% side of airliners the uh the reverse thrust<00:07:27.800> mechanism<00:07:28.800> um<00:07:29.000> this<00:07:29.120> was<00:07:29.759> uh<00:07:30.440> also 00:07:30.670 --> 00:07:30.680 align:start position:0% thrust mechanism um this was uh also 00:07:30.680 --> 00:07:33.029 align:start position:0% thrust mechanism um this was uh also uses<00:07:31.599> so<00:07:31.840> what<00:07:32.080> the<00:07:32.160> microcontroller<00:07:32.840> for 00:07:33.029 --> 00:07:33.039 align:start position:0% uses so what the microcontroller for 00:07:33.039 --> 00:07:35.670 align:start position:0% uses so what the microcontroller for that<00:07:33.479> also<00:07:33.680> uses<00:07:33.960> formal<00:07:34.319> proofing<00:07:35.160> um<00:07:35.319> I<00:07:35.440> know 00:07:35.670 --> 00:07:35.680 align:start position:0% that also uses formal proofing um I know 00:07:35.680 --> 00:07:38.670 align:start position:0% that also uses formal proofing um I know that<00:07:35.919> because<00:07:36.440> my<00:07:36.680> old<00:07:37.120> University<00:07:38.120> um<00:07:38.280> helps 00:07:38.670 --> 00:07:38.680 align:start position:0% that because my old University um helps 00:07:38.680 --> 00:07:40.950 align:start position:0% that because my old University um helps develop<00:07:39.160> that<00:07:40.160> that<00:07:40.319> particular<00:07:40.680> piece<00:07:40.840> of 00:07:40.950 --> 00:07:40.960 align:start position:0% develop that that particular piece of 00:07:40.960 --> 00:07:43.550 align:start position:0% develop that that particular piece of technology<00:07:41.960> so<00:07:42.120> it's<00:07:42.280> in<00:07:42.520> use<00:07:42.919> already<00:07:43.400> but 00:07:43.550 --> 00:07:43.560 align:start position:0% technology so it's in use already but 00:07:43.560 --> 00:07:46.830 align:start position:0% technology so it's in use already but it's<00:07:43.759> not<00:07:44.080> it's<00:07:44.240> not<00:07:44.479> widely<00:07:44.919> used<00:07:45.520> and<00:07:45.720> so<00:07:46.199> um 00:07:46.830 --> 00:07:46.840 align:start position:0% it's not it's not widely used and so um 00:07:46.840 --> 00:07:48.790 align:start position:0% it's not it's not widely used and so um it<00:07:46.919> makes<00:07:47.120> some<00:07:47.319> sense<00:07:47.560> for<00:07:48.000> contracts<00:07:48.599> which 00:07:48.790 --> 00:07:48.800 align:start position:0% it makes some sense for contracts which 00:07:48.800 --> 00:07:50.149 align:start position:0% it makes some sense for contracts which you<00:07:48.919> know<00:07:49.080> cannot<00:07:49.360> be<00:07:49.479> changed<00:07:49.800> once<00:07:50.000> they're 00:07:50.149 --> 00:07:50.159 align:start position:0% you know cannot be changed once they're 00:07:50.159 --> 00:07:53.830 align:start position:0% you know cannot be changed once they're in<00:07:50.319> there<00:07:50.800> to<00:07:50.960> use<00:07:51.240> similar 00:07:53.830 --> 00:07:53.840 align:start position:0% in there to use similar 00:07:53.840 --> 00:07:56.070 align:start position:0% in there to use similar Technologies<00:07:54.840> and<00:07:55.000> then<00:07:55.120> the<00:07:55.280> final<00:07:55.840> final 00:07:56.070 --> 00:07:56.080 align:start position:0% Technologies and then the final final 00:07:56.080 --> 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application<00:08:04.759> wants 00:08:05.029 --> 00:08:05.039 align:start position:0% the uh decentralized application wants 00:08:05.039 --> 00:08:06.390 align:start position:0% the uh decentralized application wants to<00:08:05.319> make<00:08:05.479> a<00:08:05.639> transaction<00:08:06.120> with<00:08:06.240> the 00:08:06.390 --> 00:08:06.400 align:start position:0% to make a transaction with the 00:08:06.400 --> 00:08:08.469 align:start position:0% to make a transaction with the blockchain<00:08:07.159> wants<00:08:07.479> to<00:08:07.639> sign<00:08:08.039> something<00:08:08.319> with 00:08:08.469 --> 00:08:08.479 align:start position:0% blockchain wants to sign something with 00:08:08.479 --> 00:08:11.309 align:start position:0% blockchain wants to sign something with the<00:08:08.599> user's<00:08:08.960> key<00:08:09.680> it's<00:08:10.400> really<00:08:10.960> really 00:08:11.309 --> 00:08:11.319 align:start position:0% the user's key it's really really 00:08:11.319 --> 00:08:14.149 align:start position:0% the user's key it's really really important<00:08:12.199> that<00:08:12.400> the<00:08:12.560> user<00:08:13.199> can<00:08:13.599> read<00:08:13.919> a 00:08:14.149 --> 00:08:14.159 align:start position:0% important that the user can read a 00:08:14.159 --> 00:08:16.510 align:start position:0% important that the user can read a statement<00:08:15.120> as<00:08:15.240> to<00:08:15.560> what<00:08:15.720> is<00:08:15.919> going<00:08:16.159> on<00:08:16.360> with 00:08:16.510 --> 00:08:16.520 align:start position:0% statement as to what is going on with 00:08:16.520 --> 00:08:18.469 align:start position:0% statement as to what is going on with their<00:08:16.720> key<00:08:17.039> because<00:08:17.159> if<00:08:17.280> they<00:08:17.440> can't<00:08:17.680> do<00:08:17.879> that 00:08:18.469 --> 00:08:18.479 align:start position:0% their key because if they can't do that 00:08:18.479 --> 00:08:20.830 align:start position:0% their key because if they can't do that we<00:08:18.720> you<00:08:18.800> know<00:08:18.919> we're<00:08:19.080> back<00:08:19.240> to<00:08:19.400> Step<00:08:19.639> One<00:08:20.599> um 00:08:20.830 --> 00:08:20.840 align:start position:0% we you know we're back to Step One um 00:08:20.840 --> 00:08:26.149 align:start position:0% we you know we're back to Step One um this<00:08:21.360> is<00:08:22.360> absolutely<00:08:23.319> fundamental<00:08:24.319> to<00:08:25.039> um<00:08:25.800> uh 00:08:26.149 --> 00:08:26.159 align:start position:0% this is absolutely fundamental to um uh 00:08:26.159 --> 00:08:29.070 align:start position:0% this is absolutely fundamental to um uh our<00:08:26.840> this<00:08:27.080> notion<00:08:27.560> of<00:08:27.759> having<00:08:28.120> a<00:08:28.400> a<00:08:28.800> sort<00:08:29.000> of 00:08:29.070 --> 00:08:29.080 align:start position:0% our this notion of having a a sort of 00:08:29.080 --> 00:08:31.469 align:start position:0% our this notion of having a a sort of more<00:08:29.639> trustworthy<00:08:30.639> um<00:08:30.840> interface<00:08:31.280> to 00:08:31.469 --> 00:08:31.479 align:start position:0% more trustworthy um interface to 00:08:31.479 --> 00:08:33.790 align:start position:0% more trustworthy um interface to massively<00:08:31.879> multi-user 00:08:33.790 --> 00:08:33.800 align:start position:0% massively multi-user 00:08:33.800 --> 00:08:36.070 align:start position:0% massively multi-user applications<00:08:34.800> and<00:08:34.959> so<00:08:35.320> we<00:08:35.519> we<00:08:35.680> build<00:08:35.919> the 00:08:36.070 --> 00:08:36.080 align:start position:0% applications and so we we build the 00:08:36.080 --> 00:08:38.149 align:start position:0% applications and so we we build the document<00:08:36.760> documentation<00:08:37.360> system<00:08:37.800> actually 00:08:38.149 --> 00:08:38.159 align:start position:0% document documentation system actually 00:08:38.159 --> 00:08:42.230 align:start position:0% document documentation system actually into<00:08:38.479> the<00:08:39.120> language<00:08:40.120> now<00:08:41.120> this 00:08:42.230 --> 00:08:42.240 align:start position:0% into the language now this 00:08:42.240 --> 00:08:45.590 align:start position:0% into the language now this is<00:08:43.240> you<00:08:43.399> could<00:08:43.560> argue<00:08:43.880> that<00:08:44.039> doxygen<00:08:44.880> Java<00:08:45.240> do 00:08:45.590 --> 00:08:45.600 align:start position:0% is you could argue that doxygen Java do 00:08:45.600 --> 00:08:47.269 align:start position:0% is you could argue that doxygen Java do already<00:08:45.920> sort<00:08:46.120> of<00:08:46.360> have<00:08:46.519> something<00:08:46.839> similar 00:08:47.269 --> 00:08:47.279 align:start position:0% already sort of have something similar 00:08:47.279 --> 00:08:48.790 align:start position:0% already sort of have something similar and<00:08:47.519> you<00:08:47.640> know<00:08:47.880> they<00:08:48.000> do<00:08:48.440> but<00:08:48.560> what<00:08:48.680> we're 00:08:48.790 --> 00:08:48.800 align:start position:0% and you know they do but what we're 00:08:48.800 --> 00:08:49.910 align:start position:0% and you know they do but what we're going<00:08:48.880> to<00:08:48.959> do<00:08:49.080> is<00:08:49.160> we're<00:08:49.279> going<00:08:49.360> to<00:08:49.480> build<00:08:49.680> on 00:08:49.910 --> 00:08:49.920 align:start position:0% going to do is we're going to build on 00:08:49.920 --> 00:08:51.910 align:start position:0% going to do is we're going to build on that<00:08:50.120> and<00:08:50.240> we're<00:08:50.360> going<00:08:50.440> to<00:08:50.640> have<00:08:51.080> um<00:08:51.760> uh 00:08:51.910 --> 00:08:51.920 align:start position:0% that and we're going to have um uh 00:08:51.920 --> 00:08:53.509 align:start position:0% that and we're going to have um uh rather<00:08:52.160> than<00:08:52.320> just<00:08:52.480> placeholders<00:08:53.160> actually 00:08:53.509 --> 00:08:53.519 align:start position:0% rather than just placeholders actually 00:08:53.519 --> 00:08:54.670 align:start position:0% rather than just placeholders actually have 00:08:54.670 --> 00:08:54.680 align:start position:0% have 00:08:54.680 --> 00:08:57.910 align:start position:0% have evaluatable<00:08:55.680> um<00:08:56.680> Expressions<00:08:57.399> within<00:08:57.720> the 00:08:57.910 --> 00:08:57.920 align:start position:0% evaluatable um Expressions within the 00:08:57.920 --> 00:09:01.829 align:start position:0% evaluatable um Expressions within the documentation<00:08:58.640> itself 00:09:01.829 --> 00:09:01.839 align:start position:0% 00:09:01.839 --> 00:09:04.350 align:start position:0% so<00:09:02.519> contracts<00:09:03.000> as<00:09:03.160> first<00:09:03.399> class<00:09:03.640> citizens 00:09:04.350 --> 00:09:04.360 align:start position:0% so contracts as first class citizens 00:09:04.360 --> 00:09:07.269 align:start position:0% so contracts as first class citizens here's<00:09:04.839> uh<00:09:05.160> here's<00:09:05.320> an 00:09:07.269 --> 00:09:07.279 align:start position:0% here's uh here's an 00:09:07.279 --> 00:09:10.790 align:start position:0% here's uh here's an example<00:09:08.279> and<00:09:09.000> can<00:09:09.160> I<00:09:09.320> stand<00:09:09.880> in<00:09:10.040> any<00:09:10.240> one<00:09:10.519> place 00:09:10.790 --> 00:09:10.800 align:start position:0% example and can I stand in any one place 00:09:10.800 --> 00:09:12.710 align:start position:0% example and can I stand in any one place that<00:09:10.920> will<00:09:11.079> allow<00:09:11.360> everybody<00:09:11.800> to<00:09:12.000> see 00:09:12.710 --> 00:09:12.720 align:start position:0% that will allow everybody to see 00:09:12.720 --> 00:09:14.630 align:start position:0% that will allow everybody to see probably 00:09:14.630 --> 00:09:14.640 align:start position:0% probably 00:09:14.640 --> 00:09:17.710 align:start position:0% probably not<00:09:15.640> get<00:09:15.839> most<00:09:16.040> people<00:09:16.279> I<00:09:16.399> guess<00:09:17.040> um<00:09:17.399> so<00:09:17.560> you 00:09:17.710 --> 00:09:17.720 align:start position:0% not get most people I guess um so you 00:09:17.720 --> 00:09:19.949 align:start position:0% not get most people I guess um so you got<00:09:17.839> the<00:09:17.959> idea<00:09:18.360> you<00:09:18.480> know<00:09:18.959> people<00:09:19.160> who<00:09:19.600> code<00:09:19.839> a 00:09:19.949 --> 00:09:19.959 align:start position:0% got the idea you know people who code a 00:09:19.959 --> 00:09:23.430 align:start position:0% got the idea you know people who code a bit<00:09:20.079> in<00:09:20.200> C++<00:09:20.959> will<00:09:21.240> probably<00:09:21.880> this 00:09:23.430 --> 00:09:23.440 align:start position:0% bit in C++ will probably this 00:09:23.440 --> 00:09:27.230 align:start position:0% bit in C++ will probably this Willa<00:09:24.440> you<00:09:24.560> can<00:09:25.079> Bo<00:09:25.440> is<00:09:25.640> wrong<00:09:26.519> should<00:09:26.600> read 00:09:27.230 --> 00:09:27.240 align:start position:0% Willa you can Bo is wrong should read 00:09:27.240 --> 00:09:30.350 align:start position:0% Willa you can Bo is wrong should read function<00:09:28.240> but<00:09:28.560> uh<00:09:28.760> yeah<00:09:29.480> so<00:09:29.880> it<00:09:30.000> looks<00:09:30.200> a 00:09:30.350 --> 00:09:30.360 align:start position:0% function but uh yeah so it looks a 00:09:30.360 --> 00:09:33.470 align:start position:0% function but uh yeah so it looks a little<00:09:30.560> bit<00:09:30.760> like<00:09:30.880> a<00:09:31.079> class<00:09:32.079> as<00:09:32.200> you<00:09:32.360> might 00:09:33.470 --> 00:09:33.480 align:start position:0% little bit like a class as you might 00:09:33.480 --> 00:09:36.990 align:start position:0% little bit like a class as you might expect<00:09:34.480> and<00:09:34.600> you<00:09:34.720> got<00:09:34.880> set<00:09:35.120> and<00:09:35.399> get<00:09:36.279> yeah<00:09:36.800> you 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00:09:46.120 --> 00:09:48.790 align:start position:0% the other the other slides are correct 00:09:48.790 --> 00:09:48.800 align:start position:0% correct 00:09:48.800 --> 00:09:51.470 align:start position:0% correct um<00:09:49.800> and<00:09:50.000> then<00:09:50.160> you<00:09:50.240> would<00:09:50.440> use<00:09:50.640> it<00:09:50.880> by<00:09:51.040> saying 00:09:51.470 --> 00:09:51.480 align:start position:0% um and then you would use it by saying 00:09:51.480 --> 00:09:54.750 align:start position:0% um and then you would use it by saying right<00:09:51.680> well<00:09:51.760> we've<00:09:51.920> got<00:09:52.040> an<00:09:52.160> instance<00:09:52.519> of<00:09:52.680> this 00:09:54.750 --> 00:09:54.760 align:start position:0% right well we've got an instance of this 00:09:54.760 --> 00:09:57.630 align:start position:0% right well we've got an instance of this contract<00:09:55.760> we<00:09:56.480> ignore<00:09:56.959> how<00:09:57.079> we<00:09:57.240> actually<00:09:57.480> get 00:09:57.630 --> 00:09:57.640 align:start position:0% contract we ignore how we actually get 00:09:57.640 --> 00:10:02.389 align:start position:0% contract we ignore how we actually get that<00:09:57.800> instance<00:09:58.160> for<00:09:58.320> now<00:09:59.160> um 00:10:02.389 --> 00:10:02.399 align:start position:0% 00:10:02.399 --> 00:10:06.350 align:start position:0% set<00:10:03.399> so<00:10:03.839> super<00:10:04.160> easy<00:10:04.560> o 00:10:06.350 --> 00:10:06.360 align:start position:0% set so super easy o 00:10:06.360 --> 00:10:22.990 align:start position:0% set so super easy o style<00:10:07.360> um 00:10:22.990 --> 00:10:23.000 align:start position:0% 00:10:23.000 --> 00:10:26.230 align:start position:0% interfacing<00:10:24.000> uh<00:10:24.480> I'll<00:10:24.760> answer<00:10:25.040> that 00:10:26.230 --> 00:10:26.240 align:start position:0% interfacing uh I'll answer that 00:10:26.240 --> 00:10:27.870 align:start position:0% interfacing uh I'll answer that later 00:10:27.870 --> 00:10:27.880 align:start position:0% later 00:10:27.880 --> 00:10:31.670 align:start position:0% later so<00:10:28.880> um<00:10:29.800> if<00:10:30.000> we<00:10:30.680> uh<00:10:30.839> if<00:10:30.959> we<00:10:31.079> move<00:10:31.320> on<00:10:31.440> to<00:10:31.560> the 00:10:31.670 --> 00:10:31.680 align:start position:0% so um if we uh if we move on to the 00:10:31.680 --> 00:10:34.150 align:start position:0% so um if we uh if we move on to the storage<00:10:32.160> facilities<00:10:33.160> again<00:10:33.600> it<00:10:33.680> should<00:10:33.880> be 00:10:34.150 --> 00:10:34.160 align:start position:0% storage facilities again it should be 00:10:34.160 --> 00:10:37.269 align:start position:0% storage facilities again it should be relatively<00:10:34.720> easy<00:10:35.000> to<00:10:35.200> see<00:10:35.839> that<00:10:36.160> we<00:10:36.360> have<00:10:37.040> this 00:10:37.269 --> 00:10:37.279 align:start position:0% relatively easy to see that we have this 00:10:37.279 --> 00:10:40.350 align:start position:0% relatively easy to see that we have this notion<00:10:37.560> of<00:10:37.680> a<00:10:37.959> state<00:10:38.680> right<00:10:38.959> which<00:10:39.120> is<00:10:40.120> also 00:10:40.350 --> 00:10:40.360 align:start position:0% notion of a state right which is also 00:10:40.360 --> 00:10:42.110 align:start position:0% notion of a state right which is also known<00:10:40.600> as<00:10:40.760> you<00:10:40.880> know<00:10:41.000> the<00:10:41.160> field<00:10:41.639> the<00:10:41.800> members 00:10:42.110 --> 00:10:42.120 align:start position:0% known as you know the field the members 00:10:42.120 --> 00:10:45.509 align:start position:0% known as you know the field the members of<00:10:42.240> a<00:10:42.440> of<00:10:42.519> a<00:10:42.720> class<00:10:43.720> in<00:10:43.880> this<00:10:44.120> case<00:10:44.880> um<00:10:45.079> it's<00:10:45.279> a 00:10:45.509 --> 00:10:45.519 align:start position:0% of a of a class in this case um it's a 00:10:45.519 --> 00:10:48.190 align:start position:0% of a of a class in this case um it's a uint<00:10:46.519> and<00:10:46.639> then<00:10:46.800> we<00:10:46.920> can<00:10:47.160> Define<00:10:47.440> our<00:10:47.680> set<00:10:47.959> as 00:10:48.190 --> 00:10:48.200 align:start position:0% uint and then we can Define our set as 00:10:48.200 --> 00:10:51.550 align:start position:0% uint and then we can Define our set as just<00:10:48.800> you<00:10:48.959> know<00:10:49.240> setting<00:10:49.600> it<00:10:49.839> and<00:10:50.000> our<00:10:50.279> get<00:10:51.240> as 00:10:51.550 --> 00:10:51.560 align:start position:0% just you know setting it and our get as 00:10:51.560 --> 00:10:53.550 align:start position:0% just you know setting it and our get as as<00:10:51.720> returning<00:10:52.120> it 00:10:53.550 --> 00:10:53.560 align:start position:0% as returning it 00:10:53.560 --> 00:10:55.910 align:start position:0% as returning it so 00:10:55.910 --> 00:10:55.920 align:start position:0% so 00:10:55.920 --> 00:10:59.949 align:start position:0% so this<00:10:56.920> this<00:10:57.079> to<00:10:57.279> a<00:10:57.600> C++<00:10:58.600> programmer<00:10:59.320> will<00:10:59.440> be 00:10:59.949 --> 00:10:59.959 align:start position:0% this this to a C++ programmer will be 00:10:59.959 --> 00:11:02.710 align:start position:0% this this to a C++ programmer will be super<00:11:00.440> super<00:11:00.680> simple<00:11:01.000> but<00:11:01.160> to<00:11:01.480> a<00:11:02.040> a<00:11:02.279> ja<00:11:02.600> a 00:11:02.710 --> 00:11:02.720 align:start position:0% super super simple but to a a ja a 00:11:02.720 --> 00:11:05.150 align:start position:0% super super simple but to a a ja a JavaScript<00:11:03.240> programmer<00:11:03.639> as<00:11:03.880> well<00:11:04.880> this 00:11:05.150 --> 00:11:05.160 align:start position:0% JavaScript programmer as well this 00:11:05.160 --> 00:11:09.710 align:start position:0% JavaScript programmer as well this portion<00:11:05.480> of<00:11:05.639> it<00:11:06.320> will<00:11:06.560> also<00:11:07.079> be<00:11:08.079> reasonably 00:11:09.710 --> 00:11:09.720 align:start position:0% portion of it will also be reasonably 00:11:09.720 --> 00:11:11.990 align:start position:0% portion of it will also be reasonably familiar<00:11:10.720> the<00:11:11.000> returns<00:11:11.360> bit<00:11:11.600> is<00:11:11.680> a<00:11:11.800> bit 00:11:11.990 --> 00:11:12.000 align:start position:0% familiar the returns bit is a bit 00:11:12.000 --> 00:11:14.350 align:start position:0% familiar the returns bit is a bit different<00:11:12.480> but<00:11:12.839> and<00:11:13.000> the<00:11:13.120> fact<00:11:13.320> it's<00:11:13.560> tight 00:11:14.350 --> 00:11:14.360 align:start position:0% different but and the fact it's tight 00:11:14.360 --> 00:11:18.470 align:start position:0% different but and the fact it's tight but<00:11:15.279> can't<00:11:15.519> really<00:11:15.680> get<00:11:15.839> around 00:11:18.470 --> 00:11:18.480 align:start position:0% 00:11:18.480 --> 00:11:21.629 align:start position:0% this<00:11:19.480> now<00:11:19.639> the<00:11:19.760> storage<00:11:20.160> facilities<00:11:20.920> extend 00:11:21.629 --> 00:11:21.639 align:start position:0% this now the storage facilities extend 00:11:21.639 --> 00:11:23.910 align:start position:0% this now the storage facilities extend so<00:11:21.839> what<00:11:22.000> we<00:11:22.120> also<00:11:22.320> are<00:11:22.440> able<00:11:22.639> to<00:11:22.760> do<00:11:22.920> is<00:11:23.120> map 00:11:23.910 --> 00:11:23.920 align:start position:0% so what we also are able to do is map 00:11:23.920 --> 00:11:26.990 align:start position:0% so what we also are able to do is map and<00:11:24.079> this<00:11:24.200> is<00:11:24.320> a<00:11:24.920> fundamental<00:11:25.920> um<00:11:26.560> construct 00:11:26.990 --> 00:11:27.000 align:start position:0% and this is a fundamental um construct 00:11:27.000 --> 00:11:30.990 align:start position:0% and this is a fundamental um construct in<00:11:27.160> this<00:11:27.320> language<00:11:28.000> we<00:11:28.120> can<00:11:28.360> provide<00:11:29.040> um<00:11:29.360> um<00:11:30.320> uh 00:11:30.990 --> 00:11:31.000 align:start position:0% in this language we can provide um um uh 00:11:31.000 --> 00:11:36.629 align:start position:0% in this language we can provide um um uh mapping<00:11:32.000> from<00:11:32.920> a<00:11:33.959> uh<00:11:34.959> from<00:11:35.160> an<00:11:35.639> original 00:11:36.629 --> 00:11:36.639 align:start position:0% mapping from a uh from an original 00:11:36.639 --> 00:11:40.509 align:start position:0% mapping from a uh from an original domain<00:11:37.800> range<00:11:38.800> range<00:11:39.760> from<00:11:39.920> an<00:11:40.079> original 00:11:40.509 --> 00:11:40.519 align:start position:0% domain range range from an original 00:11:40.519 --> 00:11:42.069 align:start position:0% domain range range from an original range<00:11:40.920> in<00:11:41.079> this<00:11:41.240> case<00:11:41.560> the<00:11:41.680> range<00:11:41.880> of 00:11:42.069 --> 00:11:42.079 align:start position:0% range in this case the range of 00:11:42.079 --> 00:11:45.069 align:start position:0% range in this case the range of addresses<00:11:42.920> so<00:11:43.120> this<00:11:43.240> is<00:11:43.959> the<00:11:44.160> type<00:11:44.360> of 00:11:45.069 --> 00:11:45.079 align:start position:0% addresses so this is the type of 00:11:45.079 --> 00:11:49.350 align:start position:0% addresses so this is the type of address<00:11:46.079> U<00:11:46.279> which<00:11:46.440> is<00:11:46.600> a<00:11:47.240> 160<00:11:47.600> bit 00:11:49.350 --> 00:11:49.360 align:start position:0% address U which is a 160 bit 00:11:49.360 --> 00:11:53.470 align:start position:0% address U which is a 160 bit integer<00:11:50.360> into<00:11:51.000> some<00:11:51.320> arbitrary<00:11:52.120> uh<00:11:52.279> domain<00:11:53.200> um 00:11:53.470 --> 00:11:53.480 align:start position:0% integer into some arbitrary uh domain um 00:11:53.480 --> 00:11:55.790 align:start position:0% integer into some arbitrary uh domain um in<00:11:53.600> this<00:11:53.720> case<00:11:53.959> end<00:11:54.240> points<00:11:54.920> and<00:11:55.120> we've<00:11:55.399> we've 00:11:55.790 --> 00:11:55.800 align:start position:0% in this case end points and we've we've 00:11:55.800 --> 00:11:58.629 align:start position:0% in this case end points and we've we've specified<00:11:56.240> an<00:11:56.360> endpoint<00:11:56.880> as<00:11:57.040> being<00:11:57.720> ipv4<00:11:58.320> and4 00:11:58.629 --> 00:11:58.639 align:start position:0% specified an endpoint as being ipv4 and4 00:11:58.639 --> 00:12:00.310 align:start position:0% specified an endpoint as being ipv4 and4 this<00:11:58.720> is<00:11:58.800> a<00:11:58.880> bit 00:12:00.310 --> 00:12:00.320 align:start position:0% this is a bit 00:12:00.320 --> 00:12:04.230 align:start position:0% this is a bit see<00:12:01.320> the<00:12:01.480> syntax<00:12:01.880> is<00:12:02.040> still<00:12:02.240> up<00:12:02.399> for<00:12:03.120> up<00:12:03.279> for<00:12:03.839> uh 00:12:04.230 --> 00:12:04.240 align:start position:0% see the syntax is still up for up for uh 00:12:04.240 --> 00:12:07.629 align:start position:0% see the syntax is still up for up for uh um<00:12:04.800> alteration<00:12:05.519> if<00:12:05.720> you<00:12:06.120> uh<00:12:06.880> if<00:12:07.040> anybody<00:12:07.480> here 00:12:07.629 --> 00:12:07.639 align:start position:0% um alteration if you uh if anybody here 00:12:07.639 --> 00:12:10.269 align:start position:0% um alteration if you uh if anybody here has<00:12:07.800> some<00:12:08.000> ideas<00:12:08.440> and<00:12:09.360> to<00:12:09.600> make<00:12:09.720> it<00:12:09.880> slightly 00:12:10.269 --> 00:12:10.279 align:start position:0% has some ideas and to make it slightly 00:12:10.279 --> 00:12:11.949 align:start position:0% has some ideas and to make it slightly more<00:12:10.600> javascrip 00:12:11.949 --> 00:12:11.959 align:start position:0% more javascrip 00:12:11.959 --> 00:12:15.389 align:start position:0% more javascrip without<00:12:12.959> um<00:12:13.639> making<00:12:13.880> it<00:12:14.000> too<00:12:14.360> difficult<00:12:14.480> too 00:12:15.389 --> 00:12:15.399 align:start position:0% without um making it too difficult too 00:12:15.399 --> 00:12:17.750 align:start position:0% without um making it too difficult too cast 00:12:17.750 --> 00:12:17.760 align:start position:0% cast 00:12:17.760 --> 00:12:20.150 align:start position:0% cast um<00:12:18.760> and<00:12:18.880> then<00:12:18.959> we<00:12:19.079> have<00:12:19.199> the<00:12:19.279> idea<00:12:19.519> of<00:12:19.639> setting 00:12:20.150 --> 00:12:20.160 align:start position:0% um and then we have the idea of setting 00:12:20.160 --> 00:12:22.310 align:start position:0% um and then we have the idea of setting and<00:12:20.320> we<00:12:20.399> can<00:12:20.639> make<00:12:20.800> a<00:12:20.959> new 00:12:22.310 --> 00:12:22.320 align:start position:0% and we can make a new 00:12:22.320 --> 00:12:27.030 align:start position:0% and we can make a new one<00:12:23.320> um<00:12:23.600> assign<00:12:23.959> it<00:12:24.959> super<00:12:25.279> easy<00:12:25.639> stuff<00:12:26.639> delete 00:12:27.030 --> 00:12:27.040 align:start position:0% one um assign it super easy stuff delete 00:12:27.040 --> 00:12:32.590 align:start position:0% one um assign it super easy stuff delete for<00:12:27.279> killing<00:12:27.720> it<00:12:28.720> um 00:12:32.590 --> 00:12:32.600 align:start position:0% 00:12:32.600 --> 00:12:35.750 align:start position:0% Vari<00:12:32.920> addict<00:12:33.320> returns<00:12:34.320> so<00:12:34.839> uh<00:12:35.160> if<00:12:35.240> you<00:12:35.360> want<00:12:35.519> to 00:12:35.750 --> 00:12:35.760 align:start position:0% Vari addict returns so uh if you want to 00:12:35.760 --> 00:12:38.629 align:start position:0% Vari addict returns so uh if you want to get<00:12:36.399> the<00:12:36.560> information<00:12:36.920> of<00:12:37.040> an<00:12:37.240> address<00:12:38.120> we<00:12:38.279> can 00:12:38.629 --> 00:12:38.639 align:start position:0% get the information of an address we can 00:12:38.639 --> 00:12:45.150 align:start position:0% get the information of an address we can just<00:12:38.839> specify<00:12:39.320> the<00:12:39.800> two<00:12:40.199> return<00:12:40.880> types<00:12:41.880> easy 00:12:45.150 --> 00:12:45.160 align:start position:0% 00:12:45.160 --> 00:12:47.550 align:start position:0% enough<00:12:46.160> now<00:12:46.320> the<00:12:46.440> formal<00:12:46.800> proofing<00:12:47.240> is 00:12:47.550 --> 00:12:47.560 align:start position:0% enough now the formal proofing is 00:12:47.560 --> 00:12:48.750 align:start position:0% enough now the formal proofing is probably<00:12:47.839> the<00:12:47.959> most<00:12:48.199> interesting<00:12:48.600> and 00:12:48.750 --> 00:12:48.760 align:start position:0% probably the most interesting and 00:12:48.760 --> 00:12:51.269 align:start position:0% probably the most interesting and challenging<00:12:49.240> part<00:12:49.399> of<00:12:49.760> this<00:12:50.760> uh<00:12:50.880> I<00:12:51.000> imagine 00:12:51.269 --> 00:12:51.279 align:start position:0% challenging part of this uh I imagine 00:12:51.279 --> 00:12:53.470 align:start position:0% challenging part of this uh I imagine Christian's<00:12:51.760> looking<00:12:51.959> forward<00:12:52.279> to<00:12:52.440> that<00:12:53.279> that 00:12:53.470 --> 00:12:53.480 align:start position:0% Christian's looking forward to that that 00:12:53.480 --> 00:12:55.350 align:start position:0% Christian's looking forward to that that particular<00:12:53.880> portion<00:12:54.160> of<00:12:54.279> the 00:12:55.350 --> 00:12:55.360 align:start position:0% particular portion of the 00:12:55.360 --> 00:12:56.949 align:start position:0% particular portion of the project 00:12:56.949 --> 00:12:56.959 align:start position:0% project 00:12:56.959 --> 00:12:59.949 align:start position:0% project um<00:12:57.959> the<00:12:58.160> not<00:12:58.519> the<00:12:58.760> the<00:12:58.880> idea<00:12:59.360> behind<00:12:59.600> it<00:12:59.800> is 00:12:59.949 --> 00:12:59.959 align:start position:0% um the not the the idea behind it is 00:12:59.959 --> 00:13:02.430 align:start position:0% um the not the the idea behind it is that<00:13:00.120> we<00:13:00.320> have<00:13:00.839> uh<00:13:01.480> here's<00:13:01.680> an<00:13:01.880> example<00:13:02.199> of<00:13:02.279> a 00:13:02.430 --> 00:13:02.440 align:start position:0% that we have uh here's an example of a 00:13:02.440 --> 00:13:05.710 align:start position:0% that we have uh here's an example of a cash<00:13:02.720> contract<00:13:03.240> so<00:13:03.959> you<00:13:04.360> give<00:13:05.000> to<00:13:05.199> somebody 00:13:05.710 --> 00:13:05.720 align:start position:0% cash contract so you give to somebody 00:13:05.720 --> 00:13:07.110 align:start position:0% cash contract so you give to somebody some<00:13:06.000> amount<00:13:06.399> and<00:13:06.480> you<00:13:06.600> check<00:13:06.839> that<00:13:07.000> the 00:13:07.110 --> 00:13:07.120 align:start position:0% some amount and you check that the 00:13:07.120 --> 00:13:08.750 align:start position:0% some amount and you check that the amounts<00:13:07.480> greater<00:13:07.720> in<00:13:07.839> the<00:13:07.959> caller<00:13:08.399> balance 00:13:08.750 --> 00:13:08.760 align:start position:0% amounts greater in the caller balance 00:13:08.760 --> 00:13:10.590 align:start position:0% amounts greater in the caller balance then<00:13:08.920> you<00:13:09.079> subtract<00:13:09.519> it<00:13:09.720> and<00:13:09.920> add<00:13:10.079> it<00:13:10.240> to<00:13:10.399> the 00:13:10.590 --> 00:13:10.600 align:start position:0% then you subtract it and add it to the 00:13:10.600 --> 00:13:12.870 align:start position:0% then you subtract it and add it to the to<00:13:10.720> the<00:13:11.120> destination<00:13:12.120> check<00:13:12.360> the<00:13:12.519> balance 00:13:12.870 --> 00:13:12.880 align:start position:0% to the destination check the balance 00:13:12.880 --> 00:13:13.910 align:start position:0% to the destination check the balance that's<00:13:13.040> easy 00:13:13.910 --> 00:13:13.920 align:start position:0% that's easy 00:13:13.920 --> 00:13:16.750 align:start position:0% that's easy enough<00:13:14.920> we<00:13:15.040> can<00:13:15.199> to<00:13:15.360> do<00:13:15.440> a<00:13:15.600> mapping<00:13:16.040> so<00:13:16.320> map<00:13:16.560> our 00:13:16.750 --> 00:13:16.760 align:start position:0% enough we can to do a mapping so map our 00:13:16.760 --> 00:13:19.430 align:start position:0% enough we can to do a mapping so map our address<00:13:17.199> to<00:13:17.440> a<00:13:17.800> to<00:13:18.040> a<00:13:18.440> a<00:13:18.560> numeric<00:13:19.040> type<00:13:19.320> and 00:13:19.430 --> 00:13:19.440 align:start position:0% address to a to a a numeric type and 00:13:19.440 --> 00:13:23.389 align:start position:0% address to a to a a numeric type and that's<00:13:19.600> the<00:13:20.240> balances<00:13:21.240> again<00:13:21.600> easy 00:13:23.389 --> 00:13:23.399 align:start position:0% that's the balances again easy 00:13:23.399 --> 00:13:25.389 align:start position:0% that's the balances again easy enough<00:13:24.399> we<00:13:24.519> got<00:13:24.680> this 00:13:25.389 --> 00:13:25.399 align:start position:0% enough we got this 00:13:25.399 --> 00:13:27.949 align:start position:0% enough we got this construction<00:13:26.399> so<00:13:26.600> this<00:13:26.720> is<00:13:26.839> the<00:13:27.000> initializer 00:13:27.949 --> 00:13:27.959 align:start position:0% construction so this is the initializer 00:13:27.959 --> 00:13:29.710 align:start position:0% construction so this is the initializer so<00:13:28.079> we're<00:13:28.240> just<00:13:28.360> going<00:13:28.440> to<00:13:28.600> initialize<00:13:29.399> the<00:13:29.600> uh 00:13:29.710 --> 00:13:29.720 align:start position:0% so we're just going to initialize the uh 00:13:29.720 --> 00:13:31.750 align:start position:0% so we're just going to initialize the uh whoever<00:13:30.079> created<00:13:30.480> the<00:13:30.639> contract<00:13:31.040> to<00:13:31.480> you<00:13:31.600> know 00:13:31.750 --> 00:13:31.760 align:start position:0% whoever created the contract to you know 00:13:31.760 --> 00:13:34.350 align:start position:0% whoever created the contract to you know a<00:13:31.880> billion<00:13:32.199> or<00:13:32.360> whatever<00:13:33.120> some<00:13:33.440> pre-mined 00:13:34.350 --> 00:13:34.360 align:start position:0% a billion or whatever some pre-mined 00:13:34.360 --> 00:13:36.750 align:start position:0% a billion or whatever some pre-mined amount<00:13:35.240> and<00:13:35.360> then<00:13:35.440> we<00:13:35.560> have<00:13:35.639> an<00:13:35.760> invariant 00:13:36.750 --> 00:13:36.760 align:start position:0% amount and then we have an invariant 00:13:36.760 --> 00:13:38.350 align:start position:0% amount and then we have an invariant right<00:13:37.120> this<00:13:37.240> is<00:13:37.440> this<00:13:37.519> is<00:13:37.639> the<00:13:37.760> really<00:13:38.000> clever 00:13:38.350 --> 00:13:38.360 align:start position:0% right this is this is the really clever 00:13:38.360 --> 00:13:40.750 align:start position:0% right this is this is the really clever bit<00:13:38.639> so<00:13:38.800> this<00:13:38.880> is<00:13:39.000> the<00:13:39.120> bit<00:13:39.320> that<00:13:39.440> says<00:13:40.320> at<00:13:40.480> all 00:13:40.750 --> 00:13:40.760 align:start position:0% bit so this is the bit that says at all 00:13:40.760 --> 00:13:43.389 align:start position:0% bit so this is the bit that says at all times<00:13:41.240> no<00:13:41.399> matter<00:13:41.760> what<00:13:42.399> this<00:13:42.639> contract<00:13:43.120> must 00:13:43.389 --> 00:13:43.399 align:start position:0% times no matter what this contract must 00:13:43.399 --> 00:13:47.790 align:start position:0% times no matter what this contract must always<00:13:43.920> satisfy<00:13:44.920> this<00:13:45.800> piece<00:13:45.959> of<00:13:46.160> sort<00:13:46.360> of<00:13:46.839> uh 00:13:47.790 --> 00:13:47.800 align:start position:0% always satisfy this piece of sort of uh 00:13:47.800 --> 00:13:53.110 align:start position:0% always satisfy this piece of sort of uh uh<00:13:48.519> prototypical<00:13:49.519> set<00:13:50.040> theoretic<00:13:51.320> M<00:13:52.320> um<00:13:52.959> what 00:13:53.110 --> 00:13:53.120 align:start position:0% uh prototypical set theoretic M um what 00:13:53.120 --> 00:13:54.670 align:start position:0% uh prototypical set theoretic M um what we're<00:13:53.240> actually<00:13:53.440> doing<00:13:53.680> is<00:13:53.800> we're<00:13:54.079> reduce 00:13:54.670 --> 00:13:54.680 align:start position:0% we're actually doing is we're reduce 00:13:54.680 --> 00:13:55.949 align:start position:0% we're actually doing is we're reduce well<00:13:54.800> we're<00:13:54.920> going<00:13:55.040> to<00:13:55.480> um<00:13:55.600> we're<00:13:55.720> going<00:13:55.800> to 00:13:55.949 --> 00:13:55.959 align:start position:0% well we're going to um we're going to 00:13:55.959 --> 00:13:58.749 align:start position:0% well we're going to um we're going to map<00:13:56.440> the<00:13:56.600> idea<00:13:56.920> of<00:13:57.120> value<00:13:57.480> of<00:13:57.839> so<00:13:58.160> value<00:13:58.480> of 00:13:58.749 --> 00:13:58.759 align:start position:0% map the idea of value of so value of 00:13:58.759 --> 00:14:01.189 align:start position:0% map the idea of value of so value of just<00:13:59.279> in<00:13:59.399> this<00:13:59.600> case<00:13:59.800> is<00:13:59.959> the<00:14:00.160> idea<00:14:00.440> of<00:14:00.800> uh 00:14:01.189 --> 00:14:01.199 align:start position:0% just in this case is the idea of uh 00:14:01.199 --> 00:14:03.629 align:start position:0% just in this case is the idea of uh taking<00:14:01.920> each<00:14:02.320> item<00:14:02.600> in<00:14:02.720> the<00:14:02.880> balances<00:14:03.480> and 00:14:03.629 --> 00:14:03.639 align:start position:0% taking each item in the balances and 00:14:03.639 --> 00:14:05.189 align:start position:0% taking each item in the balances and just<00:14:03.800> taking<00:14:04.079> the<00:14:04.279> value<00:14:04.600> so<00:14:04.880> that<00:14:05.079> the 00:14:05.189 --> 00:14:05.199 align:start position:0% just taking the value so that the 00:14:05.199 --> 00:14:07.389 align:start position:0% just taking the value so that the balance<00:14:05.600> itself<00:14:06.040> rather<00:14:06.240> than<00:14:06.399> the<00:14:06.600> address 00:14:07.389 --> 00:14:07.399 align:start position:0% balance itself rather than the address 00:14:07.399 --> 00:14:08.910 align:start position:0% balance itself rather than the address so<00:14:07.519> we<00:14:07.639> going<00:14:07.720> to<00:14:07.800> map<00:14:08.000> that<00:14:08.079> to<00:14:08.199> balances<00:14:08.720> just 00:14:08.910 --> 00:14:08.920 align:start position:0% so we going to map that to balances just 00:14:08.920 --> 00:14:11.790 align:start position:0% so we going to map that to balances just get<00:14:09.160> a<00:14:09.519> a<00:14:09.720> set<00:14:09.880> of<00:14:10.480> addresses<00:14:11.480> and<00:14:11.600> we're<00:14:11.720> going 00:14:11.790 --> 00:14:11.800 align:start position:0% get a a set of addresses and we're going 00:14:11.800 --> 00:14:14.189 align:start position:0% get a a set of addresses and we're going to<00:14:12.040> reduce<00:14:12.440> that<00:14:12.600> set<00:14:12.759> of<00:14:12.880> addresses<00:14:13.759> with<00:14:13.880> a 00:14:14.189 --> 00:14:14.199 align:start position:0% to reduce that set of addresses with a 00:14:14.199 --> 00:14:16.269 align:start position:0% to reduce that set of addresses with a plus<00:14:14.480> operator<00:14:15.079> so<00:14:15.600> let's<00:14:15.839> to<00:14:16.000> say<00:14:16.160> we're 00:14:16.269 --> 00:14:16.279 align:start position:0% plus operator so let's to say we're 00:14:16.279 --> 00:14:18.910 align:start position:0% plus operator so let's to say we're going<00:14:16.360> to<00:14:16.519> sum<00:14:16.959> some<00:14:17.560> them<00:14:18.560> and<00:14:18.680> what<00:14:18.759> we're 00:14:18.910 --> 00:14:18.920 align:start position:0% going to sum some them and what we're 00:14:18.920 --> 00:14:21.310 align:start position:0% going to sum some them and what we're saying<00:14:19.160> is<00:14:19.320> that<00:14:19.440> should<00:14:19.839> that<00:14:20.000> sum<00:14:20.920> sum<00:14:21.160> of 00:14:21.310 --> 00:14:21.320 align:start position:0% saying is that should that sum sum of 00:14:21.320 --> 00:14:24.829 align:start position:0% saying is that should that sum sum of the<00:14:21.440> balances<00:14:22.279> should<00:14:22.519> always<00:14:22.880> equal<00:14:23.560> um<00:14:23.720> a 00:14:24.829 --> 00:14:24.839 align:start position:0% the balances should always equal um a 00:14:24.839 --> 00:14:28.710 align:start position:0% the balances should always equal um a billion<00:14:25.839> and<00:14:26.519> uh<00:14:27.279> what<00:14:27.519> the<00:14:27.839> compiler<00:14:28.399> is<00:14:28.519> able 00:14:28.710 --> 00:14:28.720 align:start position:0% billion and uh what the compiler is able 00:14:28.720 --> 00:14:30.110 align:start position:0% billion and uh what the compiler is able to<00:14:28.839> do 00:14:30.110 --> 00:14:30.120 align:start position:0% to do 00:14:30.120 --> 00:14:34.230 align:start position:0% to do is<00:14:30.639> go<00:14:30.880> through<00:14:31.720> the<00:14:32.079> only<00:14:33.079> um<00:14:33.279> non-const<00:14:34.120> the 00:14:34.230 --> 00:14:34.240 align:start position:0% is go through the only um non-const the 00:14:34.240 --> 00:14:36.030 align:start position:0% is go through the only um non-const the only<00:14:34.440> mutable<00:14:35.040> method<00:14:35.360> so<00:14:35.519> the<00:14:35.600> only<00:14:35.800> method 00:14:36.030 --> 00:14:36.040 align:start position:0% only mutable method so the only method 00:14:36.040 --> 00:14:37.470 align:start position:0% only mutable method so the only method that<00:14:36.160> actually<00:14:36.360> changes<00:14:36.720> the<00:14:36.839> state<00:14:37.199> which<00:14:37.279> is 00:14:37.470 --> 00:14:37.480 align:start position:0% that actually changes the state which is 00:14:37.480 --> 00:14:40.670 align:start position:0% that actually changes the state which is this<00:14:37.600> one<00:14:38.360> and<00:14:38.519> do<00:14:38.880> a<00:14:39.320> um<00:14:39.600> a<00:14:39.720> formal<00:14:40.160> proof<00:14:40.519> of 00:14:40.670 --> 00:14:40.680 align:start position:0% this one and do a um a formal proof of 00:14:40.680 --> 00:14:45.189 align:start position:0% this one and do a um a formal proof of this<00:14:40.880> code<00:14:41.880> to<00:14:42.120> check<00:14:42.560> that<00:14:43.160> uh<00:14:43.440> if<00:14:43.759> it's<00:14:44.759> uh<00:14:45.079> if 00:14:45.189 --> 00:14:45.199 align:start position:0% this code to check that uh if it's uh if 00:14:45.199 --> 00:14:47.550 align:start position:0% this code to check that uh if it's uh if it<00:14:45.440> satisfies<00:14:46.240> this<00:14:46.440> constraint<00:14:46.920> at<00:14:47.040> the 00:14:47.550 --> 00:14:47.560 align:start position:0% it satisfies this constraint at the 00:14:47.560 --> 00:14:51.069 align:start position:0% it satisfies this constraint at the beginning<00:14:48.560> and<00:14:48.839> this<00:14:49.000> code 00:14:51.069 --> 00:14:51.079 align:start position:0% beginning and this code 00:14:51.079 --> 00:14:53.629 align:start position:0% beginning and this code executes<00:14:52.079> um<00:14:52.399> it<00:14:52.519> will<00:14:52.720> always<00:14:53.160> satisfy<00:14:53.560> the 00:14:53.629 --> 00:14:53.639 align:start position:0% executes um it will always satisfy the 00:14:53.639 --> 00:14:55.670 align:start position:0% executes um it will always satisfy the constraint<00:14:54.040> at<00:14:54.160> the<00:14:54.240> end<00:14:54.920> and<00:14:55.360> in<00:14:55.519> this 00:14:55.670 --> 00:14:55.680 align:start position:0% constraint at the end and in this 00:14:55.680 --> 00:14:57.150 align:start position:0% constraint at the end and in this particular<00:14:56.079> case<00:14:56.279> it 00:14:57.150 --> 00:14:57.160 align:start position:0% particular case it 00:14:57.160 --> 00:14:59.550 align:start position:0% particular case it does<00:14:58.160> and<00:14:58.240> so<00:14:58.440> the<00:14:58.560> compiler<00:14:59.120> would<00:14:59.240> would<00:14:59.399> be 00:14:59.550 --> 00:14:59.560 align:start position:0% does and so the compiler would would be 00:14:59.560 --> 00:15:02.629 align:start position:0% does and so the compiler would would be happy<00:15:00.120> now<00:15:00.360> what<00:15:00.560> that<00:15:00.800> gets<00:15:01.240> the<00:15:01.680> the<00:15:02.199> um<00:15:02.440> the 00:15:02.629 --> 00:15:02.639 align:start position:0% happy now what that gets the the um the 00:15:02.639 --> 00:15:06.430 align:start position:0% happy now what that gets the the um the author<00:15:03.360> is<00:15:03.560> the<00:15:03.680> ability<00:15:04.079> to<00:15:04.320> state<00:15:05.320> in<00:15:05.440> the 00:15:06.430 --> 00:15:06.440 align:start position:0% author is the ability to state in the 00:15:06.440 --> 00:15:08.470 align:start position:0% author is the ability to state in the documentation<00:15:07.440> that 00:15:08.470 --> 00:15:08.480 align:start position:0% documentation that 00:15:08.480 --> 00:15:11.749 align:start position:0% documentation that this<00:15:09.480> for<00:15:09.759> this<00:15:09.959> line<00:15:10.199> of<00:15:10.399> code<00:15:11.000> it<00:15:11.120> says<00:15:11.600> at 00:15:11.749 --> 00:15:11.759 align:start position:0% this for this line of code it says at 00:15:11.759 --> 00:15:15.189 align:start position:0% this for this line of code it says at all<00:15:12.040> times<00:15:12.560> total<00:15:12.920> balances<00:15:13.480> will<00:15:13.680> be<00:15:14.120> a 00:15:15.189 --> 00:15:15.199 align:start position:0% all times total balances will be a 00:15:15.199 --> 00:15:18.509 align:start position:0% all times total balances will be a billion<00:15:16.199> now<00:15:16.720> someone<00:15:17.120> coming<00:15:17.399> to<00:15:17.680> this<00:15:18.120> uh 00:15:18.509 --> 00:15:18.519 align:start position:0% billion now someone coming to this uh 00:15:18.519 --> 00:15:20.069 align:start position:0% billion now someone coming to this uh this<00:15:18.680> contract<00:15:19.120> who<00:15:19.399> who<00:15:19.519> maybe<00:15:19.759> has<00:15:19.920> some 00:15:20.069 --> 00:15:20.079 align:start position:0% this contract who who maybe has some 00:15:20.079 --> 00:15:21.670 align:start position:0% this contract who who maybe has some reputation<00:15:20.639> it<00:15:20.759> could<00:15:20.880> be<00:15:21.000> like<00:15:21.120> the<00:15:21.240> ethereum 00:15:21.670 --> 00:15:21.680 align:start position:0% reputation it could be like the ethereum 00:15:21.680 --> 00:15:24.069 align:start position:0% reputation it could be like the ethereum foundation<00:15:22.240> or<00:15:22.440> the<00:15:22.560> eff<00:15:23.240> or<00:15:23.680> I<00:15:23.759> don't<00:15:23.880> know 00:15:24.069 --> 00:15:24.079 align:start position:0% foundation or the eff or I don't know 00:15:24.079 --> 00:15:26.670 align:start position:0% foundation or the eff or I don't know whoever<00:15:24.360> it<00:15:24.480> is<00:15:25.360> um<00:15:25.519> will<00:15:25.680> be<00:15:25.839> able<00:15:26.040> to<00:15:26.279> check 00:15:26.670 --> 00:15:26.680 align:start position:0% whoever it is um will be able to check 00:15:26.680 --> 00:15:30.670 align:start position:0% whoever it is um will be able to check that<00:15:27.120> that<00:15:27.320> that<00:15:27.480> line<00:15:27.680> of<00:15:27.880> code<00:15:28.480> in<00:15:28.720> the 00:15:30.670 --> 00:15:30.680 align:start position:0% that that that line of code in the 00:15:30.680 --> 00:15:33.350 align:start position:0% that that that line of code in the um<00:15:30.880> is<00:15:31.160> is<00:15:31.480> well<00:15:31.800> representative<00:15:32.680> of<00:15:33.000> the 00:15:33.350 --> 00:15:33.360 align:start position:0% um is is well representative of the 00:15:33.360 --> 00:15:35.550 align:start position:0% um is is well representative of the documentation<00:15:34.000> line<00:15:34.240> above<00:15:34.440> it<00:15:35.160> give<00:15:35.319> that<00:15:35.399> a 00:15:35.550 --> 00:15:35.560 align:start position:0% documentation line above it give that a 00:15:35.560 --> 00:15:38.150 align:start position:0% documentation line above it give that a tick<00:15:36.000> y<00:15:36.240> That's<00:15:36.480> valid<00:15:37.279> and<00:15:37.480> then<00:15:37.759> they<00:15:37.920> don't 00:15:38.150 --> 00:15:38.160 align:start position:0% tick y That's valid and then they don't 00:15:38.160 --> 00:15:39.910 align:start position:0% tick y That's valid and then they don't need<00:15:38.399> to<00:15:38.560> check<00:15:38.880> anything<00:15:39.160> else<00:15:39.519> because<00:15:39.759> the 00:15:39.910 --> 00:15:39.920 align:start position:0% need to check anything else because the 00:15:39.920 --> 00:15:41.990 align:start position:0% need to check anything else because the compiler<00:15:40.399> does<00:15:40.560> it<00:15:40.680> for<00:15:40.880> them<00:15:41.560> so<00:15:41.720> when<00:15:41.839> the 00:15:41.990 --> 00:15:42.000 align:start position:0% compiler does it for them so when the 00:15:42.000 --> 00:15:44.470 align:start position:0% compiler does it for them so when the user<00:15:42.319> comes<00:15:42.560> along<00:15:43.199> and<00:15:43.360> they<00:15:43.560> say<00:15:44.120> o<00:15:44.360> the 00:15:44.470 --> 00:15:44.480 align:start position:0% user comes along and they say o the 00:15:44.480 --> 00:15:47.389 align:start position:0% user comes along and they say o the foundation<00:15:45.079> made<00:15:45.360> this<00:15:46.279> uh<00:15:46.759> the<00:15:46.880> foundation 00:15:47.389 --> 00:15:47.399 align:start position:0% foundation made this uh the foundation 00:15:47.399 --> 00:15:50.110 align:start position:0% foundation made this uh the foundation ticked<00:15:47.800> this<00:15:47.959> line<00:15:48.240> that<00:15:48.440> says<00:15:49.440> cash<00:15:49.759> at<00:15:49.880> all 00:15:50.110 --> 00:15:50.120 align:start position:0% ticked this line that says cash at all 00:15:50.120 --> 00:15:52.790 align:start position:0% ticked this line that says cash at all times<00:15:50.360> in<00:15:50.519> this<00:15:50.680> contract<00:15:51.079> is<00:15:51.199> a<00:15:51.680> billion<00:15:52.680> they 00:15:52.790 --> 00:15:52.800 align:start position:0% times in this contract is a billion they 00:15:52.800 --> 00:15:54.670 align:start position:0% times in this contract is a billion they can<00:15:53.000> TR<00:15:53.279> it<00:15:53.480> they're<00:15:53.680> like 00:15:54.670 --> 00:15:54.680 align:start position:0% can TR it they're like 00:15:54.680 --> 00:15:57.550 align:start position:0% can TR it they're like great<00:15:55.680> and<00:15:56.079> in<00:15:56.240> none<00:15:56.440> of<00:15:56.639> that<00:15:56.839> did<00:15:57.040> we<00:15:57.199> have<00:15:57.319> to 00:15:57.550 --> 00:15:57.560 align:start position:0% great and in none of that did we have to 00:15:57.560 --> 00:16:03.230 align:start position:0% great and in none of that did we have to actually<00:15:57.920> look<00:15:58.079> at<00:15:58.240> this<00:15:58.440> code 00:16:03.230 --> 00:16:03.240 align:start position:0% 00:16:03.240 --> 00:16:06.110 align:start position:0% I'll<00:16:03.319> come<00:16:03.440> to<00:16:03.600> it<00:16:03.759> the 00:16:06.110 --> 00:16:06.120 align:start position:0% I'll come to it the 00:16:06.120 --> 00:16:09.189 align:start position:0% I'll come to it the Victor<00:16:07.120> so<00:16:08.000> um<00:16:08.199> the<00:16:08.360> final<00:16:08.639> thing<00:16:08.839> is<00:16:09.000> the 00:16:09.189 --> 00:16:09.199 align:start position:0% Victor so um the final thing is the 00:16:09.199 --> 00:16:11.350 align:start position:0% Victor so um the final thing is the inbuilt<00:16:09.639> docks<00:16:10.279> so<00:16:10.519> that's<00:16:10.839> kind<00:16:11.000> of<00:16:11.120> what<00:16:11.240> I 00:16:11.350 --> 00:16:11.360 align:start position:0% inbuilt docks so that's kind of what I 00:16:11.360 --> 00:16:13.670 align:start position:0% inbuilt docks so that's kind of what I was<00:16:11.480> saying<00:16:11.759> earlier<00:16:12.600> we<00:16:12.759> have<00:16:13.000> the<00:16:13.399> uh 00:16:13.670 --> 00:16:13.680 align:start position:0% was saying earlier we have the uh 00:16:13.680 --> 00:16:16.550 align:start position:0% was saying earlier we have the uh doxygen<00:16:14.319> style<00:16:14.560> at<00:16:14.639> the<00:16:14.720> moment<00:16:15.399> triple<00:16:16.399> uh 00:16:16.550 --> 00:16:16.560 align:start position:0% doxygen style at the moment triple uh 00:16:16.560 --> 00:16:18.110 align:start position:0% doxygen style at the moment triple uh triple<00:16:16.880> slash<00:16:17.319> which<00:16:17.480> I<00:16:17.560> guess<00:16:17.720> most<00:16:17.880> of<00:16:18.000> you 00:16:18.110 --> 00:16:18.120 align:start position:0% triple slash which I guess most of you 00:16:18.120 --> 00:16:21.590 align:start position:0% triple slash which I guess most of you are<00:16:18.279> probably<00:16:18.600> familiar<00:16:19.040> with<00:16:20.440> um<00:16:21.440> the 00:16:21.590 --> 00:16:21.600 align:start position:0% are probably familiar with um the 00:16:21.600 --> 00:16:24.230 align:start position:0% are probably familiar with um the interesting<00:16:22.079> thing<00:16:22.240> of<00:16:22.440> this<00:16:22.759> is<00:16:23.120> the<00:16:23.880> uh<00:16:24.079> the 00:16:24.230 --> 00:16:24.240 align:start position:0% interesting thing of this is the uh the 00:16:24.240 --> 00:16:26.110 align:start position:0% interesting thing of this is the uh the back<00:16:24.519> tick<00:16:24.800> so<00:16:24.920> the<00:16:25.040> back<00:16:25.240> tick<00:16:25.480> allows<00:16:25.759> us<00:16:25.880> to 00:16:26.110 --> 00:16:26.120 align:start position:0% back tick so the back tick allows us to 00:16:26.120 --> 00:16:29.269 align:start position:0% back tick so the back tick allows us to insert<00:16:27.000> um<00:16:27.279> arbitrary<00:16:28.279> uh<00:16:28.440> expressions 00:16:29.269 --> 00:16:29.279 align:start position:0% insert um arbitrary uh expressions 00:16:29.279 --> 00:16:33.430 align:start position:0% insert um arbitrary uh expressions JavaScript<00:16:29.920> Expressions<00:16:31.079> into<00:16:32.079> um<00:16:32.399> the 00:16:33.430 --> 00:16:33.440 align:start position:0% JavaScript Expressions into um the 00:16:33.440 --> 00:16:35.629 align:start position:0% JavaScript Expressions into um the documentation<00:16:34.440> so<00:16:34.759> what<00:16:34.959> this<00:16:35.160> does<00:16:35.319> is<00:16:35.440> it 00:16:35.629 --> 00:16:35.639 align:start position:0% documentation so what this does is it 00:16:35.639 --> 00:16:37.749 align:start position:0% documentation so what this does is it provides<00:16:36.079> a<00:16:36.319> notice<00:16:36.920> for<00:16:37.079> the<00:16:37.199> user<00:16:37.480> so<00:16:37.639> when 00:16:37.749 --> 00:16:37.759 align:start position:0% provides a notice for the user so when 00:16:37.759 --> 00:16:39.590 align:start position:0% provides a notice for the user so when the<00:16:37.880> user<00:16:38.240> sort<00:16:38.440> of<00:16:38.720> you<00:16:38.839> know<00:16:39.079> clicks<00:16:39.399> through 00:16:39.590 --> 00:16:39.600 align:start position:0% the user sort of you know clicks through 00:16:39.600 --> 00:16:41.629 align:start position:0% the user sort of you know clicks through on<00:16:39.720> some<00:16:39.959> dap<00:16:40.199> and<00:16:40.319> gets<00:16:40.480> a<00:16:40.639> transaction<00:16:41.519> the 00:16:41.629 --> 00:16:41.639 align:start position:0% on some dap and gets a transaction the 00:16:41.639 --> 00:16:43.430 align:start position:0% on some dap and gets a transaction the DAP<00:16:41.880> wants<00:16:42.079> to<00:16:42.279> submit<00:16:42.600> the<00:16:42.759> transaction<00:16:43.199> into 00:16:43.430 --> 00:16:43.440 align:start position:0% DAP wants to submit the transaction into 00:16:43.440 --> 00:16:44.629 align:start position:0% DAP wants to submit the transaction into the 00:16:44.629 --> 00:16:44.639 align:start position:0% the 00:16:44.639 --> 00:16:47.710 align:start position:0% the network<00:16:45.639> um<00:16:45.920> this<00:16:46.079> is<00:16:46.279> the<00:16:46.519> message<00:16:47.519> that 00:16:47.710 --> 00:16:47.720 align:start position:0% network um this is the message that 00:16:47.720 --> 00:16:51.389 align:start position:0% network um this is the message that comes<00:16:48.040> up<00:16:48.759> in<00:16:48.920> the<00:16:49.079> browser<00:16:49.800> before<00:16:50.800> it<00:16:51.000> signs 00:16:51.389 --> 00:16:51.399 align:start position:0% comes up in the browser before it signs 00:16:51.399 --> 00:16:54.030 align:start position:0% comes up in the browser before it signs it<00:16:52.040> so<00:16:52.240> there's<00:16:52.480> like<00:16:52.639> a<00:16:52.800> a<00:16:52.959> sort<00:16:53.120> of<00:16:53.319> black<00:16:53.759> box 00:16:54.030 --> 00:16:54.040 align:start position:0% it so there's like a a sort of black box 00:16:54.040 --> 00:16:56.150 align:start position:0% it so there's like a a sort of black box in<00:16:54.160> the<00:16:54.319> browser<00:16:55.000> right<00:16:55.440> that<00:16:55.600> contains<00:16:56.000> all 00:16:56.150 --> 00:16:56.160 align:start position:0% in the browser right that contains all 00:16:56.160 --> 00:16:58.069 align:start position:0% in the browser right that contains all the<00:16:56.279> secret<00:16:56.639> keys<00:16:57.199> and<00:16:57.360> ultimately<00:16:57.920> this 00:16:58.069 --> 00:16:58.079 align:start position:0% the secret keys and ultimately this 00:16:58.079 --> 00:16:59.949 align:start position:0% the secret keys and ultimately this could<00:16:58.199> be<00:16:58.399> control<00:16:59.120> actually<00:16:59.399> not<00:16:59.680> in<00:16:59.839> the 00:16:59.949 --> 00:16:59.959 align:start position:0% could be control actually not in the 00:16:59.959 --> 00:17:00.990 align:start position:0% could be control actually not in the browser<00:17:00.279> itself<00:17:00.600> but<00:17:00.680> it<00:17:00.759> could<00:17:00.880> be 00:17:00.990 --> 00:17:01.000 align:start position:0% browser itself but it could be 00:17:01.000 --> 00:17:03.430 align:start position:0% browser itself but it could be controlled<00:17:01.519> by<00:17:01.800> a<00:17:02.000> trusted<00:17:02.440> Computing 00:17:03.430 --> 00:17:03.440 align:start position:0% controlled by a trusted Computing 00:17:03.440 --> 00:17:06.110 align:start position:0% controlled by a trusted Computing portion<00:17:03.720> of<00:17:03.839> the<00:17:04.079> hardware<00:17:05.079> so<00:17:05.600> something<00:17:05.919> for 00:17:06.110 --> 00:17:06.120 align:start position:0% portion of the hardware so something for 00:17:06.120 --> 00:17:07.549 align:start position:0% portion of the hardware so something for which<00:17:06.280> even<00:17:06.439> the<00:17:06.559> operating<00:17:07.000> system<00:17:07.280> doesn't 00:17:07.549 --> 00:17:07.559 align:start position:0% which even the operating system doesn't 00:17:07.559 --> 00:17:08.750 align:start position:0% which even the operating system doesn't have 00:17:08.750 --> 00:17:08.760 align:start position:0% have 00:17:08.760 --> 00:17:11.870 align:start position:0% have access<00:17:09.760> and<00:17:10.280> what<00:17:10.559> this<00:17:11.240> this<00:17:11.520> this<00:17:11.720> would 00:17:11.870 --> 00:17:11.880 align:start position:0% access and what this this this would 00:17:11.880 --> 00:17:13.350 align:start position:0% access and what this this this would bring<00:17:12.079> up<00:17:12.199> a<00:17:12.319> message<00:17:12.600> it<00:17:12.720> would<00:17:12.880> say 00:17:13.350 --> 00:17:13.360 align:start position:0% bring up a message it would say 00:17:13.360 --> 00:17:15.069 align:start position:0% bring up a message it would say transfers<00:17:14.319> and<00:17:14.400> then<00:17:14.520> it<00:17:14.600> wouldn't<00:17:14.880> actually 00:17:15.069 --> 00:17:15.079 align:start position:0% transfers and then it wouldn't actually 00:17:15.079 --> 00:17:17.069 align:start position:0% transfers and then it wouldn't actually say<00:17:15.280> underscore<00:17:15.880> amount<00:17:16.520> right<00:17:16.640> it<00:17:16.720> would<00:17:16.880> say 00:17:17.069 --> 00:17:17.079 align:start position:0% say underscore amount right it would say 00:17:17.079 --> 00:17:18.429 align:start position:0% say underscore amount right it would say the<00:17:17.240> actual<00:17:17.520> amount<00:17:17.799> it<00:17:17.880> would<00:17:18.079> place<00:17:18.319> the 00:17:18.429 --> 00:17:18.439 align:start position:0% the actual amount it would place the 00:17:18.439 --> 00:17:20.029 align:start position:0% the actual amount it would place the amount<00:17:18.679> in<00:17:18.880> there<00:17:19.120> so<00:17:19.240> it<00:17:19.319> would<00:17:19.480> evaluate 00:17:20.029 --> 00:17:20.039 align:start position:0% amount in there so it would evaluate 00:17:20.039 --> 00:17:24.029 align:start position:0% amount in there so it would evaluate what<00:17:20.199> underscore<00:17:20.720> amount<00:17:21.120> is<00:17:22.120> and<00:17:22.280> then<00:17:23.079> um 00:17:24.029 --> 00:17:24.039 align:start position:0% what underscore amount is and then um 00:17:24.039 --> 00:17:26.110 align:start position:0% what underscore amount is and then um stream<00:17:24.400> it<00:17:24.559> into<00:17:24.839> this<00:17:25.079> into<00:17:25.319> this 00:17:26.110 --> 00:17:26.120 align:start position:0% stream it into this into this 00:17:26.120 --> 00:17:29.310 align:start position:0% stream it into this into this text<00:17:27.120> cash<00:17:27.360> from<00:17:27.520> your<00:17:27.799> account<00:17:28.520> message<00:17:29.080> call 00:17:29.310 --> 00:17:29.320 align:start position:0% text cash from your account message call 00:17:29.320 --> 00:17:30.830 align:start position:0% text cash from your account message call it<00:17:29.400> would<00:17:29.559> give<00:17:29.720> you<00:17:30.080> either<00:17:30.320> the<00:17:30.480> name<00:17:30.720> if 00:17:30.830 --> 00:17:30.840 align:start position:0% it would give you either the name if 00:17:30.840 --> 00:17:32.230 align:start position:0% it would give you either the name if you've<00:17:31.120> if<00:17:31.160> you've<00:17:31.280> got<00:17:31.400> a<00:17:31.559> name<00:17:31.799> attached<00:17:32.120> to 00:17:32.230 --> 00:17:32.240 align:start position:0% you've if you've got a name attached to 00:17:32.240 --> 00:17:33.870 align:start position:0% you've if you've got a name attached to it<00:17:32.320> if<00:17:32.520> name<00:17:32.679> rge<00:17:32.919> has<00:17:33.080> got<00:17:33.160> a<00:17:33.280> name<00:17:33.520> that<00:17:33.640> you 00:17:33.870 --> 00:17:33.880 align:start position:0% it if name rge has got a name that you 00:17:33.880 --> 00:17:36.470 align:start position:0% it if name rge has got a name that you that<00:17:33.960> you<00:17:34.080> trust<00:17:34.799> or<00:17:35.200> or<00:17:35.440> just<00:17:35.640> the<00:17:35.840> the<00:17:35.960> hex<00:17:36.280> or 00:17:36.470 --> 00:17:36.480 align:start position:0% that you trust or or just the the hex or 00:17:36.480 --> 00:17:39.110 align:start position:0% that you trust or or just the the hex or maybe<00:17:36.679> even<00:17:36.880> a<00:17:37.039> little<00:17:37.760> graphic<00:17:38.760> to<00:17:38.960> the 00:17:39.110 --> 00:17:39.120 align:start position:0% maybe even a little graphic to the 00:17:39.120 --> 00:17:41.350 align:start position:0% maybe even a little graphic to the account<00:17:39.400> controlled<00:17:39.960> by<00:17:40.400> and<00:17:40.600> then<00:17:40.960> again<00:17:41.200> the 00:17:41.350 --> 00:17:41.360 align:start position:0% account controlled by and then again the 00:17:41.360 --> 00:17:45.150 align:start position:0% account controlled by and then again the same<00:17:41.600> thing<00:17:42.240> but<00:17:42.760> but<00:17:43.000> the<00:17:43.320> um 00:17:45.150 --> 00:17:45.160 align:start position:0% same thing but but the um 00:17:45.160 --> 00:17:47.350 align:start position:0% same thing but but the um destination<00:17:46.160> returns<00:17:46.440> to<00:17:46.640> cash<00:17:47.000> don't<00:17:47.200> really 00:17:47.350 --> 00:17:47.360 align:start position:0% destination returns to cash don't really 00:17:47.360 --> 00:17:49.190 align:start position:0% destination returns to cash don't really care<00:17:47.520> about<00:17:47.720> that<00:17:48.240> and<00:17:48.360> then<00:17:48.480> You'<00:17:48.640> got<00:17:48.840> the<00:17:49.080> uh 00:17:49.190 --> 00:17:49.200 align:start position:0% care about that and then You' got the uh 00:17:49.200 --> 00:17:51.070 align:start position:0% care about that and then You' got the uh the<00:17:49.320> construction<00:17:50.039> creator<00:17:50.400> of<00:17:50.520> the<00:17:50.679> contract 00:17:51.070 --> 00:17:51.080 align:start position:0% the construction creator of the contract 00:17:51.080 --> 00:17:53.029 align:start position:0% the construction creator of the contract is<00:17:51.240> endowed<00:17:51.640> with<00:17:51.760> a<00:17:51.880> balance<00:17:52.120> of<00:17:52.280> a 00:17:53.029 --> 00:17:53.039 align:start position:0% is endowed with a balance of a 00:17:53.039 --> 00:17:56.470 align:start position:0% is endowed with a balance of a billion<00:17:54.039> that's<00:17:54.240> easy<00:17:54.640> enough<00:17:55.640> um<00:17:56.120> it<00:17:56.240> will 00:17:56.470 --> 00:17:56.480 align:start position:0% billion that's easy enough um it will 00:17:56.480 --> 00:17:59.510 align:start position:0% billion that's easy enough um it will probably<00:17:57.440> insert<00:17:57.919> m 00:17:59.510 --> 00:17:59.520 align:start position:0% probably insert m 00:17:59.520 --> 00:18:02.230 align:start position:0% probably insert m get<00:18:00.080> get<00:18:00.240> the<00:18:00.400> address<00:18:01.400> and<00:18:01.520> then<00:18:01.799> finally 00:18:02.230 --> 00:18:02.240 align:start position:0% get get the address and then finally 00:18:02.240 --> 00:18:05.070 align:start position:0% get get the address and then finally this<00:18:02.520> magic<00:18:03.000> line<00:18:04.000> total<00:18:04.400> cash<00:18:04.559> in<00:18:04.679> the<00:18:04.799> system 00:18:05.070 --> 00:18:05.080 align:start position:0% this magic line total cash in the system 00:18:05.080 --> 00:18:06.669 align:start position:0% this magic line total cash in the system is<00:18:05.200> always<00:18:05.440> a<00:18:05.640> billion<00:18:06.159> and<00:18:06.280> this<00:18:06.400> is<00:18:06.559> the 00:18:06.669 --> 00:18:06.679 align:start position:0% is always a billion and this is the 00:18:06.679 --> 00:18:10.149 align:start position:0% is always a billion and this is the thing<00:18:07.000> that<00:18:07.200> the<00:18:07.400> the<00:18:07.559> auditor<00:18:08.159> or<00:18:08.640> whoever<00:18:09.640> um 00:18:10.149 --> 00:18:10.159 align:start position:0% thing that the the auditor or whoever um 00:18:10.159 --> 00:18:12.310 align:start position:0% thing that the the auditor or whoever um whoever<00:18:10.679> is<00:18:11.679> it<00:18:11.760> could<00:18:11.880> be<00:18:12.000> that<00:18:12.080> there<00:18:12.200> are 00:18:12.310 --> 00:18:12.320 align:start position:0% whoever is it could be that there are 00:18:12.320 --> 00:18:14.149 align:start position:0% whoever is it could be that there are many<00:18:12.480> Auditors<00:18:12.919> I<00:18:12.960> mean<00:18:13.120> you<00:18:13.200> know<00:18:13.320> it's 00:18:14.149 --> 00:18:14.159 align:start position:0% many Auditors I mean you know it's 00:18:14.159 --> 00:18:17.789 align:start position:0% many Auditors I mean you know it's decentralized<00:18:15.159> um<00:18:15.360> checks<00:18:15.799> this<00:18:16.000> line<00:18:17.000> yeah 00:18:17.789 --> 00:18:17.799 align:start position:0% decentralized um checks this line yeah 00:18:17.799 --> 00:18:19.510 align:start position:0% decentralized um checks this line yeah yeah<00:18:18.039> that's<00:18:18.240> fine<00:18:18.559> that's<00:18:18.799> that<00:18:19.000> that<00:18:19.120> means 00:18:19.510 --> 00:18:19.520 align:start position:0% yeah that's fine that's that that means 00:18:19.520 --> 00:18:23.789 align:start position:0% yeah that's fine that's that that means this<00:18:20.720> and<00:18:21.720> that's<00:18:21.880> the<00:18:22.320> magic<00:18:23.320> when<00:18:23.480> the<00:18:23.559> user 00:18:23.789 --> 00:18:23.799 align:start position:0% this and that's the magic when the user 00:18:23.799 --> 00:18:26.470 align:start position:0% this and that's the magic when the user comes<00:18:24.000> to<00:18:24.120> look<00:18:24.240> at<00:18:24.360> it<00:18:25.240> there<00:18:25.520> get<00:18:26.200> an 00:18:26.470 --> 00:18:26.480 align:start position:0% comes to look at it there get an 00:18:26.480 --> 00:18:27.510 align:start position:0% comes to look at it there get an absolutely 00:18:27.510 --> 00:18:27.520 align:start position:0% absolutely 00:18:27.520 --> 00:18:31.310 align:start position:0% absolutely trustable<00:18:28.520> uh 00:18:31.310 --> 00:18:31.320 align:start position:0% 00:18:31.320 --> 00:18:35.270 align:start position:0% statement<00:18:32.320> cool<00:18:32.880> so<00:18:33.200> those<00:18:33.360> are<00:18:33.559> the<00:18:34.200> uh<00:18:34.360> basic 00:18:35.270 --> 00:18:35.280 align:start position:0% statement cool so those are the uh basic 00:18:35.280 --> 00:18:38.870 align:start position:0% statement cool so those are the uh basic uh<00:18:36.200> driving<00:18:36.880> factors<00:18:37.559> and<00:18:38.039> rough<00:18:38.440> solutions 00:18:38.870 --> 00:18:38.880 align:start position:0% uh driving factors and rough solutions 00:18:38.880 --> 00:18:41.549 align:start position:0% uh driving factors and rough solutions to<00:18:39.080> them<00:18:39.840> um<00:18:40.080> Christian<00:18:40.559> is<00:18:40.720> now<00:18:40.960> going<00:18:41.159> to<00:18:41.360> go 00:18:41.549 --> 00:18:41.559 align:start position:0% to them um Christian is now going to go 00:18:41.559 --> 00:18:43.789 align:start position:0% to them um Christian is now going to go into<00:18:42.559> a<00:18:42.720> little<00:18:42.919> more<00:18:43.120> detail<00:18:43.440> then<00:18:43.559> we'll<00:18:43.679> do 00:18:43.789 --> 00:18:43.799 align:start position:0% into a little more detail then we'll do 00:18:43.799 --> 00:18:45.390 align:start position:0% into a little more detail then we'll do a<00:18:43.960> question<00:18:44.200> and<00:18:44.400> answer<00:18:44.640> session<00:18:44.919> at<00:18:45.039> the<00:18:45.159> end 00:18:45.390 --> 00:18:45.400 align:start position:0% a question and answer session at the end 00:18:45.400 --> 00:18:51.590 align:start position:0% a question and answer session at the end and<00:18:45.720> uh<00:18:45.799> you<00:18:45.880> can<00:18:46.000> bring<00:18:46.159> up<00:18:46.280> your<00:18:46.400> points 00:18:51.590 --> 00:18:51.600 align:start position:0% 00:18:51.600 --> 00:18:53.030 align:start position:0% there<00:18:52.600> okay 00:18:53.030 --> 00:18:53.040 align:start position:0% there okay 00:18:53.040 --> 00:18:56.430 align:start position:0% there okay [Music] 00:18:56.430 --> 00:18:56.440 align:start position:0% 00:18:56.440 --> 00:18:59.950 align:start position:0% so<00:18:57.520> um<00:18:58.520> yeah 00:18:59.950 --> 00:18:59.960 align:start position:0% so um yeah 00:18:59.960 --> 00:19:03.110 align:start position:0% so um yeah now<00:19:00.960> let's<00:19:01.159> see<00:19:01.960> how<00:19:02.240> this<00:19:02.360> is<00:19:02.480> all 00:19:03.110 --> 00:19:03.120 align:start position:0% now let's see how this is all 00:19:03.120 --> 00:19:06.270 align:start position:0% now let's see how this is all implemented<00:19:04.120> um 00:19:06.270 --> 00:19:06.280 align:start position:0% implemented um 00:19:06.280 --> 00:19:08.470 align:start position:0% implemented um first<00:19:07.280> what<00:19:07.440> were<00:19:07.679> the<00:19:07.840> requirements<00:19:08.280> for 00:19:08.470 --> 00:19:08.480 align:start position:0% first what were the requirements for 00:19:08.480 --> 00:19:10.270 align:start position:0% first what were the requirements for solidity<00:19:09.080> Gavin<00:19:09.360> already<00:19:09.600> told<00:19:09.840> us<00:19:10.000> about 00:19:10.270 --> 00:19:10.280 align:start position:0% solidity Gavin already told us about 00:19:10.280 --> 00:19:11.710 align:start position:0% solidity Gavin already told us about that<00:19:10.400> so<00:19:10.559> it's<00:19:10.679> a<00:19:10.960> contract<00:19:11.280> oriented 00:19:11.710 --> 00:19:11.720 align:start position:0% that so it's a contract oriented 00:19:11.720 --> 00:19:15.669 align:start position:0% that so it's a contract oriented language<00:19:12.559> which<00:19:12.679> means<00:19:13.000> that<00:19:14.000> classes<00:19:15.000> are 00:19:15.669 --> 00:19:15.679 align:start position:0% language which means that classes are 00:19:15.679 --> 00:19:19.230 align:start position:0% language which means that classes are contracts<00:19:16.679> it<00:19:16.799> is<00:19:17.000> statically<00:19:17.799> typed<00:19:18.799> from 00:19:19.230 --> 00:19:19.240 align:start position:0% contracts it is statically typed from 00:19:19.240 --> 00:19:23.190 align:start position:0% contracts it is statically typed from the<00:19:19.400> syntax<00:19:20.240> uh<00:19:20.480> close<00:19:20.760> to<00:19:21.440> JavaScript<00:19:22.440> and 00:19:23.190 --> 00:19:23.200 align:start position:0% the syntax uh close to JavaScript and 00:19:23.200 --> 00:19:24.750 align:start position:0% the syntax uh close to JavaScript and when<00:19:23.320> you<00:19:23.640> types<00:19:23.919> to<00:19:24.039> JavaScript<00:19:24.520> you<00:19:24.600> get 00:19:24.750 --> 00:19:24.760 align:start position:0% when you types to JavaScript you get 00:19:24.760 --> 00:19:27.590 align:start position:0% when you types to JavaScript you get something<00:19:25.039> which<00:19:25.159> is<00:19:25.360> close<00:19:25.679> to<00:19:25.880> C<00:19:26.520> or 00:19:27.590 --> 00:19:27.600 align:start position:0% something which is close to C or 00:19:27.600 --> 00:19:29.789 align:start position:0% something which is close to C or C++<00:19:28.600> um<00:19:28.919> uh<00:19:29.080> the<00:19:29.159> built-in<00:19:29.520> language 00:19:29.789 --> 00:19:29.799 align:start position:0% C++ um uh the built-in language 00:19:29.799 --> 00:19:32.430 align:start position:0% C++ um uh the built-in language documentation<00:19:30.679> and<00:19:31.320> some<00:19:31.679> language<00:19:32.000> subset 00:19:32.430 --> 00:19:32.440 align:start position:0% documentation and some language subset 00:19:32.440 --> 00:19:34.630 align:start position:0% documentation and some language subset that<00:19:32.520> allows<00:19:33.159> formal<00:19:33.480> proofs<00:19:33.760> of 00:19:34.630 --> 00:19:34.640 align:start position:0% that allows formal proofs of 00:19:34.640 --> 00:19:38.070 align:start position:0% that allows formal proofs of correctness<00:19:35.640> and<00:19:36.039> yeah<00:19:36.240> so 00:19:38.070 --> 00:19:38.080 align:start position:0% correctness and yeah so 00:19:38.080 --> 00:19:40.510 align:start position:0% correctness and yeah so coincidentally<00:19:39.080> this<00:19:39.159> is<00:19:39.400> exactly<00:19:40.000> the 00:19:40.510 --> 00:19:40.520 align:start position:0% coincidentally this is exactly the 00:19:40.520 --> 00:19:43.029 align:start position:0% coincidentally this is exactly the contract<00:19:41.240> Gavin<00:19:41.720> also<00:19:41.960> showed<00:19:42.679> so<00:19:42.880> you 00:19:43.029 --> 00:19:43.039 align:start position:0% contract Gavin also showed so you 00:19:43.039 --> 00:19:48.830 align:start position:0% contract Gavin also showed so you already<00:19:43.240> know<00:19:43.880> that 00:19:48.830 --> 00:19:48.840 align:start position:0% 00:19:48.840 --> 00:19:54.990 align:start position:0% um<00:19:49.840> yeah<00:19:50.840> can<00:19:51.200> skip<00:19:52.159> then<00:19:52.720> the<00:19:53.039> uous<00:19:53.960> coin 00:19:54.990 --> 00:19:55.000 align:start position:0% um yeah can skip then the uous coin 00:19:55.000 --> 00:19:57.110 align:start position:0% um yeah can skip then the uous coin contract 00:19:57.110 --> 00:19:57.120 align:start position:0% contract 00:19:57.120 --> 00:19:59.430 align:start position:0% contract um<00:19:58.120> there<00:19:58.240> we<00:19:58.360> see<00:19:58.480> some<00:19:58.799> thing<00:19:59.000> we've<00:19:59.280> not 00:19:59.430 --> 00:19:59.440 align:start position:0% um there we see some thing we've not 00:19:59.440 --> 00:20:03.350 align:start position:0% um there we see some thing we've not seen<00:19:59.799> in<00:20:00.120> Gavin's<00:20:00.559> talk<00:20:01.720> um<00:20:02.720> the<00:20:02.880> language<00:20:03.200> is 00:20:03.350 --> 00:20:03.360 align:start position:0% seen in Gavin's talk um the language is 00:20:03.360 --> 00:20:07.390 align:start position:0% seen in Gavin's talk um the language is statically<00:20:03.840> typed<00:20:04.240> but<00:20:04.520> still<00:20:05.880> um<00:20:06.880> it's<00:20:07.080> not 00:20:07.390 --> 00:20:07.400 align:start position:0% statically typed but still um it's not 00:20:07.400 --> 00:20:09.110 align:start position:0% statically typed but still um it's not necessary<00:20:07.799> to<00:20:07.960> always<00:20:08.280> specify<00:20:08.679> the<00:20:08.840> types 00:20:09.110 --> 00:20:09.120 align:start position:0% necessary to always specify the types 00:20:09.120 --> 00:20:12.470 align:start position:0% necessary to always specify the types you<00:20:09.240> have<00:20:09.440> this<00:20:10.039> keyword<00:20:11.000> V<00:20:12.000> uh<00:20:12.120> which<00:20:12.280> can<00:20:12.360> be 00:20:12.470 --> 00:20:12.480 align:start position:0% you have this keyword V uh which can be 00:20:12.480 --> 00:20:14.430 align:start position:0% you have this keyword V uh which can be used<00:20:12.679> for<00:20:12.840> local<00:20:13.159> variables<00:20:13.919> and<00:20:14.240> it's 00:20:14.430 --> 00:20:14.440 align:start position:0% used for local variables and it's 00:20:14.440 --> 00:20:17.750 align:start position:0% used for local variables and it's similar<00:20:14.840> to<00:20:15.039> C++<00:20:15.960> 11's<00:20:16.640> Auto<00:20:17.080> keyword<00:20:17.600> which 00:20:17.750 --> 00:20:17.760 align:start position:0% similar to C++ 11's Auto keyword which 00:20:17.760 --> 00:20:20.029 align:start position:0% similar to C++ 11's Auto keyword which means<00:20:18.200> the<00:20:18.400> type<00:20:18.600> is<00:20:18.799> just<00:20:18.960> taken<00:20:19.200> from<00:20:19.440> the 00:20:20.029 --> 00:20:20.039 align:start position:0% means the type is just taken from the 00:20:20.039 --> 00:20:22.510 align:start position:0% means the type is just taken from the type<00:20:20.240> of<00:20:20.440> the<00:20:20.840> first<00:20:21.280> assignment<00:20:22.039> to<00:20:22.240> this 00:20:22.510 --> 00:20:22.520 align:start position:0% type of the first assignment to this 00:20:22.520 --> 00:20:25.830 align:start position:0% type of the first assignment to this variable<00:20:23.520> so<00:20:23.640> I<00:20:23.760> think<00:20:23.919> that's<00:20:24.120> quite 00:20:25.830 --> 00:20:25.840 align:start position:0% variable so I think that's quite 00:20:25.840 --> 00:20:33.789 align:start position:0% variable so I think that's quite convenient<00:20:26.840> um 00:20:33.789 --> 00:20:33.799 align:start position:0% 00:20:33.799 --> 00:20:37.230 align:start position:0% yeah<00:20:34.799> okay<00:20:35.159> then<00:20:35.760> uh<00:20:35.919> we<00:20:36.080> see 00:20:37.230 --> 00:20:37.240 align:start position:0% yeah okay then uh we see 00:20:37.240 --> 00:20:39.029 align:start position:0% yeah okay then uh we see something 00:20:39.029 --> 00:20:39.039 align:start position:0% something 00:20:39.039 --> 00:20:42.350 align:start position:0% something um<00:20:40.039> users<00:20:40.520> can<00:20:41.039> Define<00:20:41.360> their<00:20:41.520> own<00:20:41.799> types<00:20:42.120> so 00:20:42.350 --> 00:20:42.360 align:start position:0% um users can Define their own types so 00:20:42.360 --> 00:20:45.470 align:start position:0% um users can Define their own types so they<00:20:42.559> can<00:20:43.360> Define<00:20:43.640> structs<00:20:44.480> and<00:20:44.840> then 00:20:45.470 --> 00:20:45.480 align:start position:0% they can Define structs and then 00:20:45.480 --> 00:20:50.390 align:start position:0% they can Define structs and then mappings<00:20:46.159> can<00:20:46.720> map<00:20:47.720> basic<00:20:48.120> types<00:20:48.559> to<00:20:49.400> any<00:20:49.760> type 00:20:50.390 --> 00:20:50.400 align:start position:0% mappings can map basic types to any type 00:20:50.400 --> 00:20:53.669 align:start position:0% mappings can map basic types to any type so<00:20:50.720> we<00:20:50.840> can<00:20:51.039> have<00:20:51.280> a<00:20:51.400> struct<00:20:51.840> at<00:20:52.400> the<00:20:53.400> as<00:20:53.520> the 00:20:53.669 --> 00:20:53.679 align:start position:0% so we can have a struct at the as the 00:20:53.679 --> 00:20:55.549 align:start position:0% so we can have a struct at the as the value<00:20:54.000> type<00:20:54.240> we<00:20:54.320> can<00:20:54.480> also<00:20:54.720> have<00:20:55.039> mappings 00:20:55.549 --> 00:20:55.559 align:start position:0% value type we can also have mappings 00:20:55.559 --> 00:20:58.590 align:start position:0% value type we can also have mappings again<00:20:55.760> as<00:20:55.960> value<00:20:56.720> types<00:20:57.720> we<00:20:57.840> can<00:20:57.960> also<00:20:58.159> have 00:20:58.590 --> 00:20:58.600 align:start position:0% again as value types we can also have 00:20:58.600 --> 00:21:00.390 align:start position:0% again as value types we can also have contracts<00:20:58.960> as<00:20:59.159> value 00:21:00.390 --> 00:21:00.400 align:start position:0% contracts as value 00:21:00.400 --> 00:21:02.990 align:start position:0% contracts as value types 00:21:02.990 --> 00:21:03.000 align:start position:0% types 00:21:03.000 --> 00:21:07.029 align:start position:0% types and<00:21:04.000> um<00:21:04.840> this<00:21:05.000> vote<00:21:05.480> is<00:21:05.799> the<00:21:06.159> the<00:21:06.280> struct<00:21:06.679> type 00:21:07.029 --> 00:21:07.039 align:start position:0% and um this vote is the the struct type 00:21:07.039 --> 00:21:08.590 align:start position:0% and um this vote is the the struct type here<00:21:07.320> so<00:21:07.640> you 00:21:08.590 --> 00:21:08.600 align:start position:0% here so you 00:21:08.600 --> 00:21:10.470 align:start position:0% here so you can 00:21:10.470 --> 00:21:10.480 align:start position:0% can 00:21:10.480 --> 00:21:13.269 align:start position:0% can retrieve<00:21:11.480> from<00:21:11.720> the<00:21:11.880> storage<00:21:12.440> from<00:21:12.720> this<00:21:13.080> this 00:21:13.269 --> 00:21:13.279 align:start position:0% retrieve from the storage from this this 00:21:13.279 --> 00:21:15.390 align:start position:0% retrieve from the storage from this this mapping<00:21:13.720> here<00:21:14.440> uh<00:21:14.760> the<00:21:14.919> value<00:21:15.200> which<00:21:15.279> is 00:21:15.390 --> 00:21:15.400 align:start position:0% mapping here uh the value which is 00:21:15.400 --> 00:21:17.669 align:start position:0% mapping here uh the value which is stored<00:21:15.760> at<00:21:15.880> the<00:21:16.000> senders 00:21:17.669 --> 00:21:17.679 align:start position:0% stored at the senders 00:21:17.679 --> 00:21:22.909 align:start position:0% stored at the senders address<00:21:18.679> and<00:21:19.080> then<00:21:20.080> yeah<00:21:20.440> assign<00:21:21.440> values<00:21:21.960> to 00:21:22.909 --> 00:21:22.919 align:start position:0% address and then yeah assign values to 00:21:22.919 --> 00:21:24.230 align:start position:0% address and then yeah assign values to this<00:21:23.159> local 00:21:24.230 --> 00:21:24.240 align:start position:0% this local 00:21:24.240 --> 00:21:26.909 align:start position:0% this local variable<00:21:25.240> but<00:21:25.559> this<00:21:25.720> doesn't<00:21:26.039> really<00:21:26.360> so<00:21:26.720> this 00:21:26.909 --> 00:21:26.919 align:start position:0% variable but this doesn't really so this 00:21:26.919 --> 00:21:28.230 align:start position:0% variable but this doesn't really so this this<00:21:27.120> actually<00:21:27.360> assigns<00:21:27.679> it<00:21:27.840> directly<00:21:28.120> to 00:21:28.230 --> 00:21:28.240 align:start position:0% this actually assigns it directly to 00:21:28.240 --> 00:21:31.149 align:start position:0% this actually assigns it directly to stor<00:21:28.919> because<00:21:29.559> vote<00:21:29.880> is<00:21:30.120> not<00:21:30.720> a<00:21:30.880> local 00:21:31.149 --> 00:21:31.159 align:start position:0% stor because vote is not a local 00:21:31.159 --> 00:21:32.510 align:start position:0% stor because vote is not a local variable<00:21:31.520> that<00:21:31.600> is<00:21:31.720> stored<00:21:32.000> on<00:21:32.080> the<00:21:32.200> stack 00:21:32.510 --> 00:21:32.520 align:start position:0% variable that is stored on the stack 00:21:32.520 --> 00:21:35.110 align:start position:0% variable that is stored on the stack it's<00:21:32.679> just<00:21:32.799> a<00:21:32.960> reference<00:21:33.360> to<00:21:33.559> the<00:21:33.919> storage<00:21:34.919> so 00:21:35.110 --> 00:21:35.120 align:start position:0% it's just a reference to the storage so 00:21:35.120 --> 00:21:37.590 align:start position:0% it's just a reference to the storage so you<00:21:35.279> don't<00:21:35.720> you<00:21:35.880> can<00:21:36.279> yeah<00:21:36.840> directly<00:21:37.279> access 00:21:37.590 --> 00:21:37.600 align:start position:0% you don't you can yeah directly access 00:21:37.600 --> 00:21:42.190 align:start position:0% you don't you can yeah directly access storage 00:21:42.190 --> 00:21:42.200 align:start position:0% 00:21:42.200 --> 00:21:45.190 align:start position:0% here<00:21:43.200> okay<00:21:43.640> um<00:21:43.919> some<00:21:44.120> details<00:21:44.440> about<00:21:44.840> the 00:21:45.190 --> 00:21:45.200 align:start position:0% here okay um some details about the 00:21:45.200 --> 00:21:47.390 align:start position:0% here okay um some details about the compilation 00:21:47.390 --> 00:21:47.400 align:start position:0% compilation 00:21:47.400 --> 00:21:50.549 align:start position:0% compilation process<00:21:48.400> it<00:21:48.600> consists<00:21:48.919> of<00:21:49.080> six<00:21:49.320> stages<00:21:50.320> uh<00:21:50.440> the 00:21:50.549 --> 00:21:50.559 align:start position:0% process it consists of six stages uh the 00:21:50.559 --> 00:21:53.269 align:start position:0% process it consists of six stages uh the first<00:21:50.799> stage<00:21:51.120> is<00:21:51.520> just<00:21:51.960> parsing<00:21:52.960> after 00:21:53.269 --> 00:21:53.279 align:start position:0% first stage is just parsing after 00:21:53.279 --> 00:21:55.870 align:start position:0% first stage is just parsing after parsing<00:21:53.760> we<00:21:53.960> have<00:21:54.400> the<00:21:55.159> basic<00:21:55.520> abstract 00:21:55.870 --> 00:21:55.880 align:start position:0% parsing we have the basic abstract 00:21:55.880 --> 00:21:57.870 align:start position:0% parsing we have the basic abstract syntax<00:21:56.200> tree<00:21:56.919> so<00:21:57.080> we<00:21:57.200> know<00:21:57.360> the<00:21:57.480> structure<00:21:57.760> of 00:21:57.870 --> 00:21:57.880 align:start position:0% syntax tree so we know the structure of 00:21:57.880 --> 00:21:59.549 align:start position:0% syntax tree so we know the structure of the<00:21:58.039> program 00:21:59.549 --> 00:21:59.559 align:start position:0% the program 00:21:59.559 --> 00:22:01.269 align:start position:0% the program uh<00:21:59.720> the<00:21:59.840> next<00:22:00.039> step<00:22:00.360> is<00:22:00.720> resolving 00:22:01.269 --> 00:22:01.279 align:start position:0% uh the next step is resolving 00:22:01.279 --> 00:22:02.830 align:start position:0% uh the next step is resolving identifiers 00:22:02.830 --> 00:22:02.840 align:start position:0% identifiers 00:22:02.840 --> 00:22:06.990 align:start position:0% identifiers so<00:22:03.840> words<00:22:04.799> identifiers<00:22:05.799> strings<00:22:06.400> can<00:22:06.640> mean 00:22:06.990 --> 00:22:07.000 align:start position:0% so words identifiers strings can mean 00:22:07.000 --> 00:22:09.510 align:start position:0% so words identifiers strings can mean can<00:22:07.159> refer<00:22:07.480> to<00:22:08.120> user<00:22:08.480> defined<00:22:08.799> type<00:22:09.039> names 00:22:09.510 --> 00:22:09.520 align:start position:0% can refer to user defined type names 00:22:09.520 --> 00:22:11.950 align:start position:0% can refer to user defined type names they<00:22:09.640> can<00:22:09.840> refer<00:22:10.159> to<00:22:10.679> function<00:22:11.080> names 00:22:11.950 --> 00:22:11.960 align:start position:0% they can refer to function names 00:22:11.960 --> 00:22:13.870 align:start position:0% they can refer to function names whatever<00:22:12.400> and<00:22:12.880> these<00:22:13.000> are 00:22:13.870 --> 00:22:13.880 align:start position:0% whatever and these are 00:22:13.880 --> 00:22:16.710 align:start position:0% whatever and these are all<00:22:14.880> resolved<00:22:15.400> in<00:22:15.600> their<00:22:15.799> respective<00:22:16.200> scope 00:22:16.710 --> 00:22:16.720 align:start position:0% all resolved in their respective scope 00:22:16.720 --> 00:22:19.750 align:start position:0% all resolved in their respective scope and<00:22:17.559> assigned<00:22:17.960> in<00:22:18.080> the<00:22:18.200> abstract<00:22:18.559> syntax 00:22:19.750 --> 00:22:19.760 align:start position:0% and assigned in the abstract syntax 00:22:19.760 --> 00:22:22.230 align:start position:0% and assigned in the abstract syntax stream<00:22:20.760> and<00:22:20.919> after<00:22:21.159> that<00:22:21.320> step<00:22:21.679> it's<00:22:21.880> possible 00:22:22.230 --> 00:22:22.240 align:start position:0% stream and after that step it's possible 00:22:22.240 --> 00:22:25.990 align:start position:0% stream and after that step it's possible to<00:22:23.000> infer<00:22:23.360> and<00:22:23.520> check<00:22:23.799> the<00:22:23.960> types<00:22:24.400> so<00:22:25.400> that 00:22:25.990 --> 00:22:26.000 align:start position:0% to infer and check the types so that 00:22:26.000 --> 00:22:30.350 align:start position:0% to infer and check the types so that assignments<00:22:27.000> do<00:22:27.159> not<00:22:27.360> conflict<00:22:27.760> in<00:22:27.919> types 00:22:30.350 --> 00:22:30.360 align:start position:0% assignments do not conflict in types 00:22:30.360 --> 00:22:32.590 align:start position:0% assignments do not conflict in types and<00:22:31.360> functions<00:22:31.720> are<00:22:31.880> called<00:22:32.320> with<00:22:32.480> the 00:22:32.590 --> 00:22:32.600 align:start position:0% and functions are called with the 00:22:32.600 --> 00:22:34.990 align:start position:0% and functions are called with the correct<00:22:32.880> number<00:22:33.039> of<00:22:33.200> arguments<00:22:33.760> and<00:22:34.520> and<00:22:34.640> so 00:22:34.990 --> 00:22:35.000 align:start position:0% correct number of arguments and and so 00:22:35.000 --> 00:22:38.549 align:start position:0% correct number of arguments and and so on<00:22:36.000> and<00:22:36.159> after<00:22:36.520> this<00:22:36.760> third<00:22:37.080> step<00:22:37.840> uh<00:22:38.360> it's 00:22:38.549 --> 00:22:38.559 align:start position:0% on and after this third step uh it's 00:22:38.559 --> 00:22:40.710 align:start position:0% on and after this third step uh it's possible<00:22:38.840> for<00:22:39.000> an<00:22:39.120> IDE<00:22:39.520> to<00:22:39.919> actually<00:22:40.200> use<00:22:40.559> the 00:22:40.710 --> 00:22:40.720 align:start position:0% possible for an IDE to actually use the 00:22:40.720 --> 00:22:43.990 align:start position:0% possible for an IDE to actually use the abstract<00:22:41.080> inex<00:22:41.400> stre<00:22:41.720> for<00:22:42.640> things<00:22:43.039> like<00:22:43.799> uh 00:22:43.990 --> 00:22:44.000 align:start position:0% abstract inex stre for things like uh 00:22:44.000 --> 00:22:47.110 align:start position:0% abstract inex stre for things like uh autoc<00:22:44.320> completion<00:22:44.840> or 00:22:47.110 --> 00:22:47.120 align:start position:0% autoc completion or 00:22:47.120 --> 00:22:50.830 align:start position:0% autoc completion or checking<00:22:48.120> where<00:22:48.320> a<00:22:48.520> variable<00:22:49.159> is<00:22:49.640> used<00:22:50.640> and 00:22:50.830 --> 00:22:50.840 align:start position:0% checking where a variable is used and 00:22:50.840 --> 00:22:52.870 align:start position:0% checking where a variable is used and all<00:22:51.039> this<00:22:51.400> nice<00:22:51.679> stuff<00:22:51.960> we<00:22:52.080> want<00:22:52.200> to 00:22:52.870 --> 00:22:52.880 align:start position:0% all this nice stuff we want to 00:22:52.880 --> 00:22:56.190 align:start position:0% all this nice stuff we want to have<00:22:53.880> and<00:22:54.279> the<00:22:54.400> fourth<00:22:54.760> step<00:22:55.640> uh<00:22:55.880> is 00:22:56.190 --> 00:22:56.200 align:start position:0% have and the fourth step uh is 00:22:56.200 --> 00:22:59.269 align:start position:0% have and the fourth step uh is compilation<00:22:56.679> to<00:22:56.960> an<00:22:57.279> assembly<00:22:57.720> language<00:22:58.720> then 00:22:59.269 --> 00:22:59.279 align:start position:0% compilation to an assembly language then 00:22:59.279 --> 00:23:01.470 align:start position:0% compilation to an assembly language then this<00:22:59.559> Assembly<00:22:59.919> Language<00:23:00.200> is<00:23:00.320> optimized<00:23:01.279> and 00:23:01.470 --> 00:23:01.480 align:start position:0% this Assembly Language is optimized and 00:23:01.480 --> 00:23:04.950 align:start position:0% this Assembly Language is optimized and finally<00:23:01.840> compil<00:23:02.200> to<00:23:02.320> BU 00:23:04.950 --> 00:23:04.960 align:start position:0% 00:23:04.960 --> 00:23:09.029 align:start position:0% code<00:23:05.960> okay<00:23:06.200> some<00:23:06.520> details<00:23:06.880> about<00:23:07.120> the<00:23:07.360> type 00:23:09.029 --> 00:23:09.039 align:start position:0% code okay some details about the type 00:23:09.039 --> 00:23:11.310 align:start position:0% code okay some details about the type system 00:23:11.310 --> 00:23:11.320 align:start position:0% system 00:23:11.320 --> 00:23:15.549 align:start position:0% system um<00:23:12.320> statically<00:23:12.880> typed<00:23:13.320> means<00:23:14.279> uh<00:23:14.919> that<00:23:15.279> all 00:23:15.549 --> 00:23:15.559 align:start position:0% um statically typed means uh that all 00:23:15.559 --> 00:23:17.470 align:start position:0% um statically typed means uh that all expressions<00:23:16.159> in<00:23:16.320> this<00:23:16.520> language<00:23:17.120> have<00:23:17.320> a 00:23:17.470 --> 00:23:17.480 align:start position:0% expressions in this language have a 00:23:17.480 --> 00:23:19.909 align:start position:0% expressions in this language have a fixed<00:23:17.799> type<00:23:18.159> that<00:23:18.240> is<00:23:18.480> known<00:23:18.760> at<00:23:18.919> compile 00:23:19.909 --> 00:23:19.919 align:start position:0% fixed type that is known at compile 00:23:19.919 --> 00:23:22.830 align:start position:0% fixed type that is known at compile time<00:23:20.919> and<00:23:21.480> an<00:23:21.640> operation<00:23:22.320> so<00:23:22.520> it's<00:23:22.679> not 00:23:22.830 --> 00:23:22.840 align:start position:0% time and an operation so it's not 00:23:22.840 --> 00:23:24.789 align:start position:0% time and an operation so it's not possible<00:23:23.120> for<00:23:23.240> an<00:23:23.360> operation<00:23:23.799> to<00:23:24.240> involve<00:23:24.600> two 00:23:24.789 --> 00:23:24.799 align:start position:0% possible for an operation to involve two 00:23:24.799 --> 00:23:26.470 align:start position:0% possible for an operation to involve two different<00:23:25.120> types<00:23:25.559> so<00:23:25.679> you<00:23:25.840> cannot<00:23:26.200> add<00:23:26.360> a 00:23:26.470 --> 00:23:26.480 align:start position:0% different types so you cannot add a 00:23:26.480 --> 00:23:29.549 align:start position:0% different types so you cannot add a string<00:23:26.760> to<00:23:26.880> a<00:23:27.240> number<00:23:28.240> but<00:23:28.600> it<00:23:28.679> is<00:23:28.840> possible<00:23:29.159> to 00:23:29.549 --> 00:23:29.559 align:start position:0% string to a number but it is possible to 00:23:29.559 --> 00:23:32.470 align:start position:0% string to a number but it is possible to do<00:23:29.840> manual<00:23:30.240> type<00:23:30.480> conversions<00:23:31.000> so<00:23:31.240> if<00:23:31.480> you 00:23:32.470 --> 00:23:32.480 align:start position:0% do manual type conversions so if you 00:23:32.480 --> 00:23:34.789 align:start position:0% do manual type conversions so if you manually<00:23:33.360> explicitly<00:23:33.919> convert<00:23:34.320> the<00:23:34.440> integer 00:23:34.789 --> 00:23:34.799 align:start position:0% manually explicitly convert the integer 00:23:34.799 --> 00:23:38.110 align:start position:0% manually explicitly convert the integer to<00:23:35.039> string<00:23:35.360> then<00:23:35.480> you<00:23:35.559> can<00:23:35.760> add<00:23:36.240> them<00:23:37.240> and<00:23:37.960> at 00:23:38.110 --> 00:23:38.120 align:start position:0% to string then you can add them and at 00:23:38.120 --> 00:23:40.070 align:start position:0% to string then you can add them and at some<00:23:38.400> points<00:23:38.880> automatic<00:23:39.400> type<00:23:39.640> conversions 00:23:40.070 --> 00:23:40.080 align:start position:0% some points automatic type conversions 00:23:40.080 --> 00:23:44.310 align:start position:0% some points automatic type conversions are<00:23:40.279> done<00:23:40.880> if<00:23:41.880> it<00:23:42.440> makes<00:23:42.799> sense<00:23:43.400> and<00:23:43.840> if<00:23:44.080> no 00:23:44.310 --> 00:23:44.320 align:start position:0% are done if it makes sense and if no 00:23:44.320 --> 00:23:46.510 align:start position:0% are done if it makes sense and if no information<00:23:44.720> is<00:23:44.880> lost<00:23:45.159> so<00:23:45.320> we<00:23:45.400> will<00:23:45.679> see<00:23:45.880> that 00:23:46.510 --> 00:23:46.520 align:start position:0% information is lost so we will see that 00:23:46.520 --> 00:23:48.830 align:start position:0% information is lost so we will see that later<00:23:47.520> uh<00:23:47.679> the<00:23:47.880> types<00:23:48.200> that<00:23:48.320> are<00:23:48.440> currently 00:23:48.830 --> 00:23:48.840 align:start position:0% later uh the types that are currently 00:23:48.840 --> 00:23:53.950 align:start position:0% later uh the types that are currently implemented<00:23:49.840> are<00:23:51.000> uh<00:23:52.000> unsigned<00:23:52.960> integer 00:23:53.950 --> 00:23:53.960 align:start position:0% implemented are uh unsigned integer 00:23:53.960 --> 00:23:56.029 align:start position:0% implemented are uh unsigned integer signed<00:23:54.320> integers<00:23:54.840> and<00:23:55.080> hashes<00:23:55.480> of<00:23:55.679> various 00:23:56.029 --> 00:23:56.039 align:start position:0% signed integers and hashes of various 00:23:56.039 --> 00:23:59.029 align:start position:0% signed integers and hashes of various sizes<00:23:56.760> so<00:23:56.960> this<00:23:57.159> x<00:23:57.480> is<00:23:57.640> always<00:23:58.240> uh 00:23:59.029 --> 00:23:59.039 align:start position:0% sizes so this x is always uh 00:23:59.039 --> 00:24:02.149 align:start position:0% sizes so this x is always uh the<00:23:59.200> size<00:23:59.440> in<00:23:59.640> bits<00:23:59.960> from<00:24:00.159> 8<00:24:00.400> Bits<00:24:00.679> to<00:24:00.840> 256<00:24:01.840> bits 00:24:02.149 --> 00:24:02.159 align:start position:0% the size in bits from 8 Bits to 256 bits 00:24:02.159 --> 00:24:04.590 align:start position:0% the size in bits from 8 Bits to 256 bits in<00:24:02.480> 8<00:24:02.760> bit 00:24:04.590 --> 00:24:04.600 align:start position:0% in 8 bit 00:24:04.600 --> 00:24:07.549 align:start position:0% in 8 bit steps<00:24:05.600> and<00:24:06.159> the<00:24:06.320> difference<00:24:06.799> between 00:24:07.549 --> 00:24:07.559 align:start position:0% steps and the difference between 00:24:07.559 --> 00:24:10.789 align:start position:0% steps and the difference between integers<00:24:08.000> and<00:24:08.200> hashes<00:24:08.720> is<00:24:09.039> that<00:24:09.799> uh 00:24:10.789 --> 00:24:10.799 align:start position:0% integers and hashes is that uh 00:24:10.799 --> 00:24:12.110 align:start position:0% integers and hashes is that uh arithmetic<00:24:11.279> operations<00:24:11.640> are<00:24:11.760> not<00:24:11.880> allowed 00:24:12.110 --> 00:24:12.120 align:start position:0% arithmetic operations are not allowed 00:24:12.120 --> 00:24:14.630 align:start position:0% arithmetic operations are not allowed for<00:24:12.279> hashes<00:24:12.760> because<00:24:12.960> it<00:24:13.320> doesn't<00:24:13.559> make 00:24:14.630 --> 00:24:14.640 align:start position:0% for hashes because it doesn't make 00:24:14.640 --> 00:24:19.830 align:start position:0% for hashes because it doesn't make sense<00:24:15.640> and<00:24:15.880> a<00:24:16.039> special<00:24:16.440> case<00:24:16.799> of<00:24:17.799> 160<00:24:18.159> bit<00:24:18.919> hash 00:24:19.830 --> 00:24:19.840 align:start position:0% sense and a special case of 160 bit hash 00:24:19.840 --> 00:24:21.029 align:start position:0% sense and a special case of 160 bit hash is 00:24:21.029 --> 00:24:21.039 align:start position:0% is 00:24:21.039 --> 00:24:24.990 align:start position:0% is address<00:24:22.120> where<00:24:23.120> so<00:24:23.320> and<00:24:23.480> for<00:24:23.600> an<00:24:23.720> address<00:24:24.400> uh 00:24:24.990 --> 00:24:25.000 align:start position:0% address where so and for an address uh 00:24:25.000 --> 00:24:25.990 align:start position:0% address where so and for an address uh not 00:24:25.990 --> 00:24:26.000 align:start position:0% not 00:24:26.000 --> 00:24:29.510 align:start position:0% not even<00:24:27.000> bit<00:24:27.240> operations<00:24:27.640> are<00:24:27.840> allowed 00:24:29.510 --> 00:24:29.520 align:start position:0% even bit operations are allowed 00:24:29.520 --> 00:24:33.870 align:start position:0% even bit operations are allowed but<00:24:30.520> instead<00:24:30.960> you<00:24:31.279> can<00:24:32.279> yeah<00:24:32.520> want<00:24:32.840> you<00:24:33.000> can 00:24:33.870 --> 00:24:33.880 align:start position:0% but instead you can yeah want you can 00:24:33.880 --> 00:24:36.110 align:start position:0% but instead you can yeah want you can send<00:24:34.279> ether<00:24:34.640> to<00:24:34.799> that<00:24:35.000> address<00:24:35.320> or<00:24:35.559> query<00:24:36.039> the 00:24:36.110 --> 00:24:36.120 align:start position:0% send ether to that address or query the 00:24:36.120 --> 00:24:37.630 align:start position:0% send ether to that address or query the balance<00:24:36.440> at<00:24:36.600> the 00:24:37.630 --> 00:24:37.640 align:start position:0% balance at the 00:24:37.640 --> 00:24:40.870 align:start position:0% balance at the address<00:24:38.640> then<00:24:38.799> we<00:24:38.919> have<00:24:39.240> a<00:24:39.399> Boolean<00:24:39.840> type 00:24:40.870 --> 00:24:40.880 align:start position:0% address then we have a Boolean type 00:24:40.880 --> 00:24:45.630 align:start position:0% address then we have a Boolean type mapping<00:24:41.880> structs<00:24:42.480> and 00:24:45.630 --> 00:24:45.640 align:start position:0% 00:24:45.640 --> 00:24:48.070 align:start position:0% contracts<00:24:46.640> okay<00:24:46.880> later<00:24:47.399> we<00:24:47.480> will<00:24:47.640> also<00:24:47.919> have 00:24:48.070 --> 00:24:48.080 align:start position:0% contracts okay later we will also have 00:24:48.080 --> 00:24:51.750 align:start position:0% contracts okay later we will also have strings<00:24:48.760> and<00:24:49.159> but<00:24:49.279> that's<00:24:49.440> not<00:24:49.600> implemented 00:24:51.750 --> 00:24:51.760 align:start position:0% strings and but that's not implemented 00:24:51.760 --> 00:24:54.630 align:start position:0% strings and but that's not implemented yet<00:24:52.760> okay 00:24:54.630 --> 00:24:54.640 align:start position:0% yet okay 00:24:54.640 --> 00:24:59.310 align:start position:0% yet okay um<00:24:55.640> I<00:24:55.760> hope<00:24:55.960> you've<00:24:56.200> seen<00:24:56.559> this<00:24:56.919> already<00:24:57.520> so 00:24:59.310 --> 00:24:59.320 align:start position:0% um I hope you've seen this already so 00:24:59.320 --> 00:25:02.430 align:start position:0% um I hope you've seen this already so this<00:24:59.440> is<00:24:59.640> also<00:24:59.919> available<00:25:00.440> online<00:25:01.440> uh 00:25:02.430 --> 00:25:02.440 align:start position:0% this is also available online uh 00:25:02.440 --> 00:25:05.350 align:start position:0% this is also available online uh it's<00:25:03.440> the<00:25:03.559> solidity<00:25:04.039> compiler<00:25:04.760> compiled<00:25:05.200> to 00:25:05.350 --> 00:25:05.360 align:start position:0% it's the solidity compiler compiled to 00:25:05.360 --> 00:25:09.310 align:start position:0% it's the solidity compiler compiled to JavaScript<00:25:05.919> to<00:25:06.080> be<00:25:06.440> run<00:25:07.440> offline<00:25:07.840> in<00:25:07.960> a 00:25:09.310 --> 00:25:09.320 align:start position:0% JavaScript to be run offline in a 00:25:09.320 --> 00:25:12.789 align:start position:0% JavaScript to be run offline in a browser<00:25:10.559> so 00:25:12.789 --> 00:25:12.799 align:start position:0% browser so 00:25:12.799 --> 00:25:23.149 align:start position:0% browser so okay<00:25:13.799> sorry<00:25:14.399> that's<00:25:14.600> what<00:25:14.720> always 00:25:23.149 --> 00:25:23.159 align:start position:0% 00:25:23.159 --> 00:25:25.789 align:start position:0% happens<00:25:24.159> okay<00:25:24.360> so<00:25:24.600> this<00:25:24.720> is<00:25:24.799> a<00:25:25.120> basic<00:25:25.399> contract 00:25:25.789 --> 00:25:25.799 align:start position:0% happens okay so this is a basic contract 00:25:25.799 --> 00:25:28.310 align:start position:0% happens okay so this is a basic contract without<00:25:26.000> any<00:25:26.200> content<00:25:26.880> and<00:25:27.880> on<00:25:28.000> the<00:25:28.120> right 00:25:28.310 --> 00:25:28.320 align:start position:0% without any content and on the right 00:25:28.320 --> 00:25:30.990 align:start position:0% without any content and on the right right<00:25:28.480> hand<00:25:28.679> side<00:25:29.360> uh<00:25:29.600> we 00:25:30.990 --> 00:25:31.000 align:start position:0% right hand side uh we 00:25:31.000 --> 00:25:34.470 align:start position:0% right hand side uh we see<00:25:32.000> the<00:25:32.159> compiled<00:25:32.520> op<00:25:32.720> codes<00:25:33.520> the<00:25:33.720> compiled 00:25:34.470 --> 00:25:34.480 align:start position:0% see the compiled op codes the compiled 00:25:34.480 --> 00:25:36.590 align:start position:0% see the compiled op codes the compiled binary<00:25:34.880> or<00:25:35.279> hex<00:25:35.559> version<00:25:35.799> of<00:25:35.919> the 00:25:36.590 --> 00:25:36.600 align:start position:0% binary or hex version of the 00:25:36.600 --> 00:25:39.269 align:start position:0% binary or hex version of the binary<00:25:37.600> um<00:25:37.960> more<00:25:38.200> detailed 00:25:39.269 --> 00:25:39.279 align:start position:0% binary um more detailed 00:25:39.279 --> 00:25:41.750 align:start position:0% binary um more detailed assembly<00:25:40.279> and<00:25:40.440> at<00:25:40.600> the<00:25:40.720> bottom<00:25:41.200> we<00:25:41.360> have<00:25:41.600> the 00:25:41.750 --> 00:25:41.760 align:start position:0% assembly and at the bottom we have the 00:25:41.760 --> 00:25:44.430 align:start position:0% assembly and at the bottom we have the abstract<00:25:42.120> syntax 00:25:44.430 --> 00:25:44.440 align:start position:0% abstract syntax 00:25:44.440 --> 00:25:45.950 align:start position:0% abstract syntax stream 00:25:45.950 --> 00:25:45.960 align:start position:0% stream 00:25:45.960 --> 00:25:49.950 align:start position:0% stream um<00:25:46.960> and<00:25:47.200> if<00:25:47.880> I<00:25:48.880> enter<00:25:49.200> something<00:25:49.440> in<00:25:49.559> the 00:25:49.950 --> 00:25:49.960 align:start position:0% um and if I enter something in the 00:25:49.960 --> 00:25:52.750 align:start position:0% um and if I enter something in the function<00:25:50.960> we<00:25:51.120> will<00:25:51.320> see<00:25:51.960> the<00:25:52.120> types<00:25:52.480> that<00:25:52.600> are 00:25:52.750 --> 00:25:52.760 align:start position:0% function we will see the types that are 00:25:52.760 --> 00:25:55.470 align:start position:0% function we will see the types that are inferred<00:25:53.520> from<00:25:53.880> these<00:25:54.480> uh<00:25:54.600> literal<00:25:55.159> so<00:25:55.360> it's 00:25:55.470 --> 00:25:55.480 align:start position:0% inferred from these uh literal so it's 00:25:55.480 --> 00:25:58.830 align:start position:0% inferred from these uh literal so it's an<00:25:56.440> so<00:25:57.440> the<00:25:57.559> type<00:25:57.720> of<00:25:57.880> literal<00:25:58.320> is<00:25:58.440> always<00:25:58.720> the 00:25:58.830 --> 00:25:58.840 align:start position:0% an so the type of literal is always the 00:25:58.840 --> 00:26:01.110 align:start position:0% an so the type of literal is always the smallest<00:25:59.279> type<00:25:59.480> where<00:25:59.600> it<00:25:59.760> fits<00:26:00.559> in<00:26:00.720> this<00:26:00.880> case 00:26:01.110 --> 00:26:01.120 align:start position:0% smallest type where it fits in this case 00:26:01.120 --> 00:26:05.149 align:start position:0% smallest type where it fits in this case it's<00:26:01.240> an<00:26:01.760> 8bit<00:26:02.320> unsigned<00:26:02.960> integer<00:26:03.960> and<00:26:04.159> if<00:26:04.360> we 00:26:05.149 --> 00:26:05.159 align:start position:0% it's an 8bit unsigned integer and if we 00:26:05.159 --> 00:26:07.350 align:start position:0% it's an 8bit unsigned integer and if we add<00:26:05.360> an<00:26:05.480> 8bit<00:26:06.279> unset<00:26:06.559> integer<00:26:06.840> to<00:26:06.960> an<00:26:07.039> 8bit 00:26:07.350 --> 00:26:07.360 align:start position:0% add an 8bit unset integer to an 8bit 00:26:07.360 --> 00:26:10.750 align:start position:0% add an 8bit unset integer to an 8bit unset<00:26:07.640> integer<00:26:08.039> we<00:26:08.279> again<00:26:08.520> get<00:26:08.640> an<00:26:08.760> 8bit<00:26:09.159> unset 00:26:10.750 --> 00:26:10.760 align:start position:0% unset integer we again get an 8bit unset 00:26:10.760 --> 00:26:14.830 align:start position:0% unset integer we again get an 8bit unset integer<00:26:12.080> nothing<00:26:13.080> too<00:26:13.360> fancy<00:26:14.320> so<00:26:14.520> it<00:26:14.640> gets 00:26:14.830 --> 00:26:14.840 align:start position:0% integer nothing too fancy so it gets 00:26:14.840 --> 00:26:17.750 align:start position:0% integer nothing too fancy so it gets interesting<00:26:15.279> when<00:26:15.600> we<00:26:16.600> use 00:26:17.750 --> 00:26:17.760 align:start position:0% interesting when we use 00:26:17.760 --> 00:26:22.590 align:start position:0% interesting when we use larger<00:26:18.760> values<00:26:19.279> so<00:26:20.240> 7,000<00:26:20.840> is<00:26:20.960> a<00:26:21.120> 16<00:26:21.440> bit<00:26:22.000> anide 00:26:22.590 --> 00:26:22.600 align:start position:0% larger values so 7,000 is a 16 bit anide 00:26:22.600 --> 00:26:25.310 align:start position:0% larger values so 7,000 is a 16 bit anide integer<00:26:22.960> and<00:26:23.080> we<00:26:23.399> add<00:26:24.399> an<00:26:24.520> 8<00:26:24.799> bit<00:26:24.960> onside 00:26:25.310 --> 00:26:25.320 align:start position:0% integer and we add an 8 bit onside 00:26:25.320 --> 00:26:28.710 align:start position:0% integer and we add an 8 bit onside integer<00:26:25.600> to<00:26:25.720> a<00:26:25.840> 16<00:26:26.159> bit<00:26:26.880> onside<00:26:27.320> integer<00:26:28.600> this 00:26:28.710 --> 00:26:28.720 align:start position:0% integer to a 16 bit onside integer this 00:26:28.720 --> 00:26:31.149 align:start position:0% integer to a 16 bit onside integer this 8bit<00:26:29.480> integer<00:26:30.000> is<00:26:30.159> implicitly<00:26:30.640> converted<00:26:31.000> to 00:26:31.149 --> 00:26:31.159 align:start position:0% 8bit integer is implicitly converted to 00:26:31.159 --> 00:26:34.269 align:start position:0% 8bit integer is implicitly converted to a<00:26:31.240> 16bit<00:26:31.760> integer<00:26:32.480> and<00:26:33.399> and<00:26:33.640> what<00:26:33.760> if<00:26:33.880> you<00:26:34.039> add 00:26:34.269 --> 00:26:34.279 align:start position:0% a 16bit integer and and what if you add 00:26:34.279 --> 00:26:39.510 align:start position:0% a 16bit integer and and what if you add like<00:26:34.640> 200 00:26:39.510 --> 00:26:39.520 align:start position:0% 00:26:39.520 --> 00:26:43.269 align:start position:0% 200<00:26:40.520> the<00:26:40.679> type<00:26:40.960> system<00:26:41.600> ignores<00:26:42.360> overflow<00:26:43.120> so 00:26:43.269 --> 00:26:43.279 align:start position:0% 200 the type system ignores overflow so 00:26:43.279 --> 00:26:49.909 align:start position:0% 200 the type system ignores overflow so it's<00:26:43.480> just<00:26:43.799> about<00:26:45.080> um<00:26:46.080> yeah<00:26:46.240> so<00:26:46.960> uh 00:26:49.909 --> 00:26:49.919 align:start position:0% 00:26:49.919 --> 00:26:54.789 align:start position:0% one<00:26:50.919> we<00:26:51.120> always<00:26:51.399> know<00:26:51.720> that<00:26:51.919> the<00:26:52.120> type<00:26:52.520> of<00:26:52.679> a<00:26:53.559> of 00:26:54.789 --> 00:26:54.799 align:start position:0% one we always know that the type of a of 00:26:54.799 --> 00:26:57.549 align:start position:0% one we always know that the type of a of uh<00:26:55.799> the<00:26:55.960> result<00:26:56.240> of<00:26:56.360> a<00:26:56.520> binary<00:26:56.880> operation<00:26:57.399> is 00:26:57.549 --> 00:26:57.559 align:start position:0% uh the result of a binary operation is 00:26:57.559 --> 00:27:01.230 align:start position:0% uh the result of a binary operation is one<00:26:57.720> of<00:26:57.840> the<00:26:58.000> types<00:26:58.240> typ<00:26:58.480> of<00:26:58.600> the 00:27:01.230 --> 00:27:01.240 align:start position:0% 00:27:01.240 --> 00:27:07.029 align:start position:0% operant<00:27:02.240> so<00:27:02.480> only<00:27:02.760> one<00:27:03.000> of<00:27:03.120> the<00:27:03.279> operant<00:27:03.919> is 00:27:07.029 --> 00:27:07.039 align:start position:0% 00:27:07.039 --> 00:27:10.149 align:start position:0% converted<00:27:08.039> and<00:27:08.919> so<00:27:09.200> we<00:27:09.320> can<00:27:09.480> now<00:27:09.720> assign<00:27:10.000> that 00:27:10.149 --> 00:27:10.159 align:start position:0% converted and so we can now assign that 00:27:10.159 --> 00:27:13.789 align:start position:0% converted and so we can now assign that to<00:27:10.279> a 00:27:13.789 --> 00:27:13.799 align:start position:0% 00:27:13.799 --> 00:27:16.669 align:start position:0% variable<00:27:14.799> and<00:27:14.960> we<00:27:15.080> will<00:27:15.240> see<00:27:15.480> that 00:27:16.669 --> 00:27:16.679 align:start position:0% variable and we will see that 00:27:16.679 --> 00:27:22.029 align:start position:0% variable and we will see that X<00:27:17.679> will<00:27:17.919> have<00:27:18.240> type<00:27:18.720> 16<00:27:19.120> bit 00:27:22.029 --> 00:27:22.039 align:start position:0% 00:27:22.039 --> 00:27:25.389 align:start position:0% uncen<00:27:23.039> okay<00:27:23.399> what<00:27:23.559> happens<00:27:23.880> if<00:27:24.080> we<00:27:24.799> if<00:27:24.919> we<00:27:25.120> want 00:27:25.389 --> 00:27:25.399 align:start position:0% uncen okay what happens if we if we want 00:27:25.399 --> 00:27:29.549 align:start position:0% uncen okay what happens if we if we want X<00:27:25.640> to<00:27:25.799> be<00:27:25.919> an<00:27:26.000> 8bit<00:27:26.480> integer 00:27:29.549 --> 00:27:29.559 align:start position:0% 00:27:29.559 --> 00:27:32.110 align:start position:0% we<00:27:29.760> get<00:27:29.919> the<00:27:30.080> error<00:27:30.600> that<00:27:31.200> the<00:27:31.360> 16bit<00:27:31.840> integer 00:27:32.110 --> 00:27:32.120 align:start position:0% we get the error that the 16bit integer 00:27:32.120 --> 00:27:33.269 align:start position:0% we get the error that the 16bit integer that<00:27:32.200> is<00:27:32.320> on<00:27:32.399> the<00:27:32.520> right<00:27:32.720> hand<00:27:32.880> side<00:27:33.039> is<00:27:33.120> not 00:27:33.269 --> 00:27:33.279 align:start position:0% that is on the right hand side is not 00:27:33.279 --> 00:27:34.950 align:start position:0% that is on the right hand side is not convertible<00:27:33.679> Tobit<00:27:34.200> integer<00:27:34.520> on<00:27:34.600> the<00:27:34.760> left 00:27:34.950 --> 00:27:34.960 align:start position:0% convertible Tobit integer on the left 00:27:34.960 --> 00:27:39.070 align:start position:0% convertible Tobit integer on the left hand 00:27:39.070 --> 00:27:39.080 align:start position:0% 00:27:39.080 --> 00:27:43.350 align:start position:0% side<00:27:40.080> okay<00:27:40.480> something<00:27:41.480> that<00:27:41.720> is<00:27:42.720> perhaps<00:27:43.080> also 00:27:43.350 --> 00:27:43.360 align:start position:0% side okay something that is perhaps also 00:27:43.360 --> 00:27:47.149 align:start position:0% side okay something that is perhaps also interesting<00:27:43.880> is<00:27:44.760> what<00:27:44.960> happens<00:27:45.360> if<00:27:45.559> we 00:27:47.149 --> 00:27:47.159 align:start position:0% interesting is what happens if we 00:27:47.159 --> 00:27:52.990 align:start position:0% interesting is what happens if we add<00:27:48.159> a<00:27:48.320> negative<00:27:48.720> number<00:27:48.960> to<00:27:49.080> a<00:27:49.240> positive 00:27:52.990 --> 00:27:53.000 align:start position:0% 00:27:53.000 --> 00:27:56.230 align:start position:0% number<00:27:54.000> so<00:27:55.000> the<00:27:55.200> compiler<00:27:55.600> complains<00:27:56.039> that<00:27:56.120> it 00:27:56.230 --> 00:27:56.240 align:start position:0% number so the compiler complains that it 00:27:56.240 --> 00:27:58.990 align:start position:0% number so the compiler complains that it cannot<00:27:56.480> find<00:27:56.640> the<00:27:56.760> common<00:27:57.080> type 00:27:58.990 --> 00:27:59.000 align:start position:0% cannot find the common type 00:27:59.000 --> 00:28:03.789 align:start position:0% cannot find the common type and<00:28:00.360> so<00:28:01.360> the<00:28:01.559> type<00:28:01.760> of<00:28:01.919> minus<00:28:02.240> one<00:28:02.640> is<00:28:03.399> signed 00:28:03.789 --> 00:28:03.799 align:start position:0% and so the type of minus one is signed 00:28:03.799 --> 00:28:07.269 align:start position:0% and so the type of minus one is signed bit<00:28:04.159> integer<00:28:05.159> of<00:28:05.360> eight<00:28:05.600> bits<00:28:06.480> and<00:28:06.760> eight<00:28:07.120> is 00:28:07.269 --> 00:28:07.279 align:start position:0% bit integer of eight bits and eight is 00:28:07.279 --> 00:28:09.230 align:start position:0% bit integer of eight bits and eight is an<00:28:07.480> unsign<00:28:07.919> integer<00:28:08.200> of<00:28:08.320> eight 00:28:09.230 --> 00:28:09.240 align:start position:0% an unsign integer of eight 00:28:09.240 --> 00:28:12.710 align:start position:0% an unsign integer of eight bits<00:28:10.240> and<00:28:10.880> so<00:28:11.360> you<00:28:11.519> cannot<00:28:11.840> convert<00:28:12.240> one<00:28:12.480> into 00:28:12.710 --> 00:28:12.720 align:start position:0% bits and so you cannot convert one into 00:28:12.720 --> 00:28:15.310 align:start position:0% bits and so you cannot convert one into the<00:28:12.840> other<00:28:13.799> so<00:28:14.000> there's<00:28:14.240> no<00:28:14.360> common<00:28:14.679> type<00:28:15.200> of 00:28:15.310 --> 00:28:15.320 align:start position:0% the other so there's no common type of 00:28:15.320 --> 00:28:17.509 align:start position:0% the other so there's no common type of course<00:28:15.519> we<00:28:15.640> know<00:28:15.960> that<00:28:16.559> both<00:28:16.760> of<00:28:16.919> them<00:28:17.240> can<00:28:17.360> be 00:28:17.509 --> 00:28:17.519 align:start position:0% course we know that both of them can be 00:28:17.519 --> 00:28:20.509 align:start position:0% course we know that both of them can be converted<00:28:17.960> to<00:28:18.240> an<00:28:18.880> assigned<00:28:19.440> integer<00:28:19.919> of<00:28:20.080> 16 00:28:20.509 --> 00:28:20.519 align:start position:0% converted to an assigned integer of 16 00:28:20.519 --> 00:28:24.190 align:start position:0% converted to an assigned integer of 16 bits<00:28:20.880> without<00:28:21.519> losing<00:28:21.880> any<00:28:22.480> information<00:28:23.480> but 00:28:24.190 --> 00:28:24.200 align:start position:0% bits without losing any information but 00:28:24.200 --> 00:28:26.830 align:start position:0% bits without losing any information but because<00:28:24.399> of<00:28:24.559> this<00:28:24.720> restriction<00:28:25.519> I<00:28:25.640> told<00:28:26.360> uh 00:28:26.830 --> 00:28:26.840 align:start position:0% because of this restriction I told uh 00:28:26.840 --> 00:28:28.750 align:start position:0% because of this restriction I told uh this<00:28:26.960> is<00:28:27.080> not<00:28:27.240> done<00:28:27.399> automatically<00:28:28.480> but<00:28:28.640> we 00:28:28.750 --> 00:28:28.760 align:start position:0% this is not done automatically but we 00:28:28.760 --> 00:28:30.669 align:start position:0% this is not done automatically but we can<00:28:28.960> of<00:28:29.080> course<00:28:29.279> force<00:28:29.640> that 00:28:30.669 --> 00:28:30.679 align:start position:0% can of course force that 00:28:30.679 --> 00:28:33.149 align:start position:0% can of course force that manually<00:28:31.679> and<00:28:31.880> convert<00:28:32.240> this<00:28:32.440> minus<00:28:32.760> one<00:28:32.960> to 00:28:33.149 --> 00:28:33.159 align:start position:0% manually and convert this minus one to 00:28:33.159 --> 00:28:35.870 align:start position:0% manually and convert this minus one to an<00:28:33.480> 16bit<00:28:34.399> side 00:28:35.870 --> 00:28:35.880 align:start position:0% an 16bit side 00:28:35.880 --> 00:28:40.990 align:start position:0% an 16bit side integer<00:28:36.880> and<00:28:37.080> then<00:28:37.880> it<00:28:38.080> works<00:28:38.960> and<00:28:39.960> X<00:28:40.279> is<00:28:40.480> also 00:28:40.990 --> 00:28:41.000 align:start position:0% integer and then it works and X is also 00:28:41.000 --> 00:28:45.230 align:start position:0% integer and then it works and X is also assigned<00:28:42.000> integer<00:28:42.399> of<00:28:42.559> 60 00:28:45.230 --> 00:28:45.240 align:start position:0% 00:28:45.240 --> 00:28:49.149 align:start position:0% minuts<00:28:46.240> okay<00:28:46.840> you<00:28:46.960> check<00:28:47.159> it<00:28:47.360> also<00:28:47.559> on<00:28:47.720> the 00:28:49.149 --> 00:28:49.159 align:start position:0% minuts okay you check it also on the 00:28:49.159 --> 00:28:51.990 align:start position:0% minuts okay you check it also on the variabl<00:28:50.159> what<00:28:50.240> do<00:28:50.320> you<00:28:50.480> mean<00:28:51.480> if<00:28:51.559> you<00:28:51.760> have 00:28:51.990 --> 00:28:52.000 align:start position:0% variabl what do you mean if you have 00:28:52.000 --> 00:28:58.509 align:start position:0% variabl what do you mean if you have varable 00:28:58.509 --> 00:28:58.519 align:start position:0% 00:28:58.519 --> 00:29:00.269 align:start position:0% so<00:28:59.000> can<00:28:59.120> we<00:28:59.279> do<00:28:59.480> the 00:29:00.269 --> 00:29:00.279 align:start position:0% so can we do the 00:29:00.279 --> 00:29:06.830 align:start position:0% so can we do the question<00:29:01.279> it<00:29:01.399> works<00:29:01.600> on<00:29:01.919> arbitrary 00:29:06.830 --> 00:29:06.840 align:start position:0% 00:29:06.840 --> 00:29:09.110 align:start position:0% Expressions<00:29:07.840> okay 00:29:09.110 --> 00:29:09.120 align:start position:0% Expressions okay 00:29:09.120 --> 00:29:11.669 align:start position:0% Expressions okay um<00:29:10.120> the 00:29:11.669 --> 00:29:11.679 align:start position:0% um the 00:29:11.679 --> 00:29:15.070 align:start position:0% um the optimizer<00:29:12.720> um<00:29:13.720> so<00:29:14.120> solidity<00:29:14.679> does<00:29:14.880> not 00:29:15.070 --> 00:29:15.080 align:start position:0% optimizer um so solidity does not 00:29:15.080 --> 00:29:18.269 align:start position:0% optimizer um so solidity does not compile<00:29:15.480> to<00:29:15.760> lll<00:29:16.360> but<00:29:16.519> it<00:29:16.799> compiles<00:29:17.279> directly 00:29:18.269 --> 00:29:18.279 align:start position:0% compile to lll but it compiles directly 00:29:18.279 --> 00:29:22.549 align:start position:0% compile to lll but it compiles directly to<00:29:19.279> evm<00:29:19.720> assembly<00:29:20.279> and<00:29:20.399> it<00:29:20.559> uses<00:29:21.559> lll's 00:29:22.549 --> 00:29:22.559 align:start position:0% to evm assembly and it uses lll's 00:29:22.559 --> 00:29:25.310 align:start position:0% to evm assembly and it uses lll's assembly<00:29:23.279> class<00:29:24.279> which<00:29:24.480> also<00:29:24.679> includes<00:29:25.159> the 00:29:25.310 --> 00:29:25.320 align:start position:0% assembly class which also includes the 00:29:25.320 --> 00:29:29.310 align:start position:0% assembly class which also includes the optimizer<00:29:26.120> so<00:29:27.039> if<00:29:27.159> we<00:29:27.320> improve<00:29:28.120> the<00:29:28.320> optimizer 00:29:29.310 --> 00:29:29.320 align:start position:0% optimizer so if we improve the optimizer 00:29:29.320 --> 00:29:33.190 align:start position:0% optimizer so if we improve the optimizer then<00:29:30.000> uh<00:29:30.559> solidity<00:29:31.320> Serpent<00:29:31.880> and<00:29:32.039> lll<00:29:32.640> will 00:29:33.190 --> 00:29:33.200 align:start position:0% then uh solidity Serpent and lll will 00:29:33.200 --> 00:29:35.750 align:start position:0% then uh solidity Serpent and lll will benefit<00:29:33.559> from<00:29:33.720> these 00:29:35.750 --> 00:29:35.760 align:start position:0% benefit from these 00:29:35.760 --> 00:29:38.070 align:start position:0% benefit from these improvements<00:29:36.760> um<00:29:37.039> I<00:29:37.159> already<00:29:37.519> did<00:29:37.799> some 00:29:38.070 --> 00:29:38.080 align:start position:0% improvements um I already did some 00:29:38.080 --> 00:29:43.070 align:start position:0% improvements um I already did some improvements<00:29:38.600> so<00:29:39.600> the<00:29:39.960> lnl<00:29:40.880> optimizer<00:29:41.880> is<00:29:42.519> so 00:29:43.070 --> 00:29:43.080 align:start position:0% improvements so the lnl optimizer is so 00:29:43.080 --> 00:29:44.950 align:start position:0% improvements so the lnl optimizer is so most<00:29:43.279> of<00:29:43.399> the<00:29:43.519> steps<00:29:43.760> in<00:29:43.880> the<00:29:43.960> LL<00:29:44.279> Optimizer<00:29:44.760> is 00:29:44.950 --> 00:29:44.960 align:start position:0% most of the steps in the LL Optimizer is 00:29:44.960 --> 00:29:48.630 align:start position:0% most of the steps in the LL Optimizer is just<00:29:45.720> a<00:29:45.880> pattern<00:29:46.159> of<00:29:46.279> op<00:29:46.919> codes<00:29:47.919> is<00:29:48.120> mapped<00:29:48.440> to 00:29:48.630 --> 00:29:48.640 align:start position:0% just a pattern of op codes is mapped to 00:29:48.640 --> 00:29:51.669 align:start position:0% just a pattern of op codes is mapped to another<00:29:49.120> to<00:29:49.320> to<00:29:49.840> yeah<00:29:50.360> to<00:29:50.640> another<00:29:51.200> set<00:29:51.360> of<00:29:51.480> op 00:29:51.669 --> 00:29:51.679 align:start position:0% another to to yeah to another set of op 00:29:51.679 --> 00:29:53.750 align:start position:0% another to to yeah to another set of op codes<00:29:52.399> and<00:29:52.640> if<00:29:52.880> the<00:29:53.000> number<00:29:53.200> of<00:29:53.360> up<00:29:53.519> codes 00:29:53.750 --> 00:29:53.760 align:start position:0% codes and if the number of up codes 00:29:53.760 --> 00:29:55.750 align:start position:0% codes and if the number of up codes decreases<00:29:54.320> then<00:29:54.559> this<00:29:54.799> is 00:29:55.750 --> 00:29:55.760 align:start position:0% decreases then this is 00:29:55.760 --> 00:29:58.389 align:start position:0% decreases then this is applied<00:29:56.760> and<00:29:57.159> one<00:29:57.279> of<00:29:57.440> these<00:29:57.640> patterns<00:29:58.120> is 00:29:58.389 --> 00:29:58.399 align:start position:0% applied and one of these patterns is 00:29:58.399 --> 00:30:02.070 align:start position:0% applied and one of these patterns is constant<00:29:58.720> folding<00:29:59.200> so<00:29:59.440> if<00:29:59.559> you<00:30:00.039> write<00:30:00.440> 7<00:30:00.880> +<00:30:01.120> 8 00:30:02.070 --> 00:30:02.080 align:start position:0% constant folding so if you write 7 + 8 00:30:02.080 --> 00:30:04.430 align:start position:0% constant folding so if you write 7 + 8 then<00:30:02.240> the<00:30:02.360> optimizer<00:30:02.919> will<00:30:03.080> not<00:30:04.000> do<00:30:04.240> this 00:30:04.430 --> 00:30:04.440 align:start position:0% then the optimizer will not do this 00:30:04.440 --> 00:30:07.350 align:start position:0% then the optimizer will not do this addition<00:30:05.240> at<00:30:06.039> runtime<00:30:06.519> but<00:30:06.640> it<00:30:06.720> will<00:30:06.919> do<00:30:07.080> it<00:30:07.200> at 00:30:07.350 --> 00:30:07.360 align:start position:0% addition at runtime but it will do it at 00:30:07.360 --> 00:30:10.389 align:start position:0% addition at runtime but it will do it at compile<00:30:07.679> time<00:30:07.840> and<00:30:08.000> just<00:30:08.240> push<00:30:08.760> directly<00:30:09.120> push 00:30:10.389 --> 00:30:10.399 align:start position:0% compile time and just push directly push 00:30:10.399 --> 00:30:13.710 align:start position:0% compile time and just push directly push 15<00:30:11.399> and<00:30:11.600> I<00:30:11.760> added<00:30:12.360> some<00:30:12.559> other<00:30:12.760> operants<00:30:13.600> uh 00:30:13.710 --> 00:30:13.720 align:start position:0% 15 and I added some other operants uh 00:30:13.720 --> 00:30:15.509 align:start position:0% 15 and I added some other operants uh for<00:30:14.000> this<00:30:14.159> constant<00:30:14.440> folding<00:30:14.880> because<00:30:15.200> they 00:30:15.509 --> 00:30:15.519 align:start position:0% for this constant folding because they 00:30:15.519 --> 00:30:18.630 align:start position:0% for this constant folding because they were<00:30:15.960> more<00:30:16.200> widely<00:30:16.480> used<00:30:17.320> in 00:30:18.630 --> 00:30:18.640 align:start position:0% were more widely used in 00:30:18.640 --> 00:30:21.789 align:start position:0% were more widely used in solidity<00:30:19.640> and<00:30:19.799> another<00:30:20.039> optimization<00:30:21.039> is<00:30:21.440> uh 00:30:21.789 --> 00:30:21.799 align:start position:0% solidity and another optimization is uh 00:30:21.799 --> 00:30:25.350 align:start position:0% solidity and another optimization is uh pop<00:30:22.480> optimization<00:30:23.480> this<00:30:23.640> happens<00:30:24.039> if<00:30:24.240> you<00:30:25.240> if 00:30:25.350 --> 00:30:25.360 align:start position:0% pop optimization this happens if you if 00:30:25.360 --> 00:30:27.710 align:start position:0% pop optimization this happens if you if you<00:30:25.440> do<00:30:25.600> some<00:30:26.159> computation<00:30:27.159> and<00:30:27.279> it<00:30:27.399> does<00:30:27.559> not 00:30:27.710 --> 00:30:27.720 align:start position:0% you do some computation and it does not 00:30:27.720 --> 00:30:31.029 align:start position:0% you do some computation and it does not have<00:30:28.120> side<00:30:28.519> effects<00:30:29.519> and<00:30:29.799> you<00:30:30.279> just<00:30:30.559> discard 00:30:31.029 --> 00:30:31.039 align:start position:0% have side effects and you just discard 00:30:31.039 --> 00:30:32.750 align:start position:0% have side effects and you just discard the<00:30:31.159> result<00:30:31.399> of<00:30:31.559> the<00:30:31.799> of<00:30:31.919> the<00:30:32.039> computation 00:30:32.750 --> 00:30:32.760 align:start position:0% the result of the of the computation 00:30:32.760 --> 00:30:38.149 align:start position:0% the result of the of the computation then<00:30:33.000> the<00:30:33.159> optimizer<00:30:34.120> removes<00:30:34.559> the<00:30:34.679> whole 00:30:38.149 --> 00:30:38.159 align:start position:0% 00:30:38.159 --> 00:30:49.830 align:start position:0% computation<00:30:39.159> okay<00:30:39.360> let's<00:30:39.519> see<00:30:39.679> an 00:30:49.830 --> 00:30:49.840 align:start position:0% 00:30:49.840 --> 00:31:04.350 align:start position:0% example<00:30:50.840> okay<00:30:51.159> first<00:30:51.399> without<00:30:51.679> optimizer 00:31:04.350 --> 00:31:04.360 align:start position:0% 00:31:04.360 --> 00:31:06.470 align:start position:0% um<00:31:05.279> okay<00:31:05.559> so<00:31:05.760> we<00:31:05.880> have<00:31:06.039> to<00:31:06.120> look<00:31:06.240> at<00:31:06.360> the 00:31:06.470 --> 00:31:06.480 align:start position:0% um okay so we have to look at the 00:31:06.480 --> 00:31:09.950 align:start position:0% um okay so we have to look at the assembly<00:31:06.919> now<00:31:07.559> um<00:31:08.559> from<00:31:08.760> tag<00:31:09.080> zero<00:31:09.440> to<00:31:09.760> this 00:31:09.950 --> 00:31:09.960 align:start position:0% assembly now um from tag zero to this 00:31:09.960 --> 00:31:11.629 align:start position:0% assembly now um from tag zero to this tag<00:31:10.200> three<00:31:10.519> that's<00:31:10.799> the<00:31:11.000> the<00:31:11.120> body<00:31:11.360> of<00:31:11.480> the 00:31:11.629 --> 00:31:11.639 align:start position:0% tag three that's the the body of the 00:31:11.639 --> 00:31:15.590 align:start position:0% tag three that's the the body of the function<00:31:12.639> and<00:31:12.799> we<00:31:12.919> see<00:31:13.200> it<00:31:13.480> it<00:31:13.600> does<00:31:14.360> push<00:31:14.679> zero 00:31:15.590 --> 00:31:15.600 align:start position:0% function and we see it it does push zero 00:31:15.600 --> 00:31:18.509 align:start position:0% function and we see it it does push zero that<00:31:15.840> is<00:31:16.399> it<00:31:16.600> initial<00:31:17.600> it<00:31:17.799> initializes<00:31:18.360> the 00:31:18.509 --> 00:31:18.519 align:start position:0% that is it initial it initializes the 00:31:18.519 --> 00:31:21.110 align:start position:0% that is it initial it initializes the local<00:31:18.840> variable<00:31:19.200> to<00:31:19.519> zero<00:31:20.480> then<00:31:20.639> it<00:31:20.760> pushes 00:31:21.110 --> 00:31:21.120 align:start position:0% local variable to zero then it pushes 00:31:21.120 --> 00:31:24.149 align:start position:0% local variable to zero then it pushes the<00:31:21.200> two<00:31:21.399> operant<00:31:21.799> 8<00:31:22.000> and<00:31:22.159> seven<00:31:22.519> adds<00:31:23.159> them 00:31:24.149 --> 00:31:24.159 align:start position:0% the two operant 8 and seven adds them 00:31:24.159 --> 00:31:28.509 align:start position:0% the two operant 8 and seven adds them and<00:31:24.559> this<00:31:25.200> uh<00:31:25.559> swap<00:31:26.559> stores<00:31:27.000> it<00:31:28.200> at<00:31:28.360> the 00:31:28.509 --> 00:31:28.519 align:start position:0% and this uh swap stores it at the 00:31:28.519 --> 00:31:32.070 align:start position:0% and this uh swap stores it at the location<00:31:28.799> of<00:31:29.000> X<00:31:29.519> and<00:31:30.480> pop<00:31:31.279> removes<00:31:31.720> the<00:31:31.799> old 00:31:32.070 --> 00:31:32.080 align:start position:0% location of X and pop removes the old 00:31:32.080 --> 00:31:34.029 align:start position:0% location of X and pop removes the old value<00:31:32.320> of 00:31:34.029 --> 00:31:34.039 align:start position:0% value of 00:31:34.039 --> 00:31:39.789 align:start position:0% value of x<00:31:35.039> and<00:31:35.240> if<00:31:35.440> we<00:31:35.960> activate<00:31:36.320> the 00:31:39.789 --> 00:31:39.799 align:start position:0% 00:31:39.799 --> 00:31:42.789 align:start position:0% optimizer<00:31:40.799> so<00:31:41.080> it<00:31:41.320> pushes<00:31:42.000> zero<00:31:42.399> and<00:31:42.519> then<00:31:42.639> it 00:31:42.789 --> 00:31:42.799 align:start position:0% optimizer so it pushes zero and then it 00:31:42.799 --> 00:31:45.269 align:start position:0% optimizer so it pushes zero and then it pushes<00:31:43.320> F<00:31:43.600> which<00:31:43.720> is 00:31:45.269 --> 00:31:45.279 align:start position:0% pushes F which is 00:31:45.279 --> 00:31:47.870 align:start position:0% pushes F which is 15<00:31:46.279> swaps<00:31:46.679> it<00:31:46.840> stores<00:31:47.200> it<00:31:47.320> and<00:31:47.440> removes<00:31:47.760> the 00:31:47.870 --> 00:31:47.880 align:start position:0% 15 swaps it stores it and removes the 00:31:47.880 --> 00:31:50.629 align:start position:0% 15 swaps it stores it and removes the old<00:31:48.120> value<00:31:48.880> so<00:31:49.080> this<00:31:49.200> is<00:31:49.519> not<00:31:49.760> yet<00:31:49.960> optimal 00:31:50.629 --> 00:31:50.639 align:start position:0% old value so this is not yet optimal 00:31:50.639 --> 00:31:53.509 align:start position:0% old value so this is not yet optimal because<00:31:51.519> we<00:31:51.639> know<00:31:52.519> it's<00:31:52.679> not<00:31:52.880> necessary<00:31:53.240> to 00:31:53.509 --> 00:31:53.519 align:start position:0% because we know it's not necessary to 00:31:53.519 --> 00:31:56.909 align:start position:0% because we know it's not necessary to initialize<00:31:54.000> X<00:31:54.159> to<00:31:54.399> Zero<00:31:55.039> when<00:31:55.279> we<00:31:56.279> change<00:31:56.600> it 00:31:56.909 --> 00:31:56.919 align:start position:0% initialize X to Zero when we change it 00:31:56.919 --> 00:31:58.350 align:start position:0% initialize X to Zero when we change it its<00:31:57.159> value<00:31:57.480> afterward 00:31:58.350 --> 00:31:58.360 align:start position:0% its value afterward 00:31:58.360 --> 00:32:01.509 align:start position:0% its value afterward but<00:31:59.080> yeah<00:32:00.080> Optimizer<00:32:00.559> is<00:32:00.720> not<00:32:00.880> finished<00:32:01.240> yet<00:32:01.399> I 00:32:01.509 --> 00:32:01.519 align:start position:0% but yeah Optimizer is not finished yet I 00:32:01.519 --> 00:32:05.789 align:start position:0% but yeah Optimizer is not finished yet I would<00:32:01.799> say<00:32:02.960> um<00:32:03.960> to<00:32:04.080> see<00:32:04.360> Pop<00:32:04.559> optimization<00:32:05.480> we 00:32:05.789 --> 00:32:05.799 align:start position:0% would say um to see Pop optimization we 00:32:05.799 --> 00:32:08.789 align:start position:0% would say um to see Pop optimization we have<00:32:05.960> to<00:32:06.120> remove<00:32:06.480> this 00:32:08.789 --> 00:32:08.799 align:start position:0% 00:32:08.799 --> 00:32:13.789 align:start position:0% x<00:32:09.799> let's 00:32:13.789 --> 00:32:13.799 align:start position:0% 00:32:13.799 --> 00:32:15.750 align:start position:0% see 00:32:15.750 --> 00:32:15.760 align:start position:0% see 00:32:15.760 --> 00:32:20.590 align:start position:0% see no<00:32:16.760> we<00:32:16.960> also<00:32:17.159> have<00:32:17.279> to<00:32:17.399> remove<00:32:17.639> the<00:32:17.760> local 00:32:20.590 --> 00:32:20.600 align:start position:0% 00:32:20.600 --> 00:32:23.789 align:start position:0% variable<00:32:21.600> so<00:32:22.440> yeah<00:32:22.600> what<00:32:22.720> happens<00:32:23.080> here<00:32:23.360> now 00:32:23.789 --> 00:32:23.799 align:start position:0% variable so yeah what happens here now 00:32:23.799 --> 00:32:26.269 align:start position:0% variable so yeah what happens here now is<00:32:24.760> okay<00:32:24.960> yeah<00:32:25.320> Tex<00:32:25.679> zero<00:32:26.039> that's<00:32:26.159> the 00:32:26.269 --> 00:32:26.279 align:start position:0% is okay yeah Tex zero that's the 00:32:26.279 --> 00:32:30.710 align:start position:0% is okay yeah Tex zero that's the function<00:32:26.600> body<00:32:27.039> and<00:32:27.440> nothing<00:32:27.679> Happ 00:32:30.710 --> 00:32:30.720 align:start position:0% 00:32:30.720 --> 00:32:35.669 align:start position:0% happens 00:32:35.669 --> 00:32:35.679 align:start position:0% 00:32:35.679 --> 00:32:39.269 align:start position:0% okay<00:32:36.679> um<00:32:37.320> how<00:32:37.480> does<00:32:37.760> c<00:32:38.159> to<00:32:38.320> use<00:32:38.720> memory<00:32:39.039> and 00:32:39.269 --> 00:32:39.279 align:start position:0% okay um how does c to use memory and 00:32:39.279 --> 00:32:42.389 align:start position:0% okay um how does c to use memory and storage<00:32:40.480> um<00:32:41.480> we've<00:32:41.639> already<00:32:41.840> seen<00:32:42.159> everything 00:32:42.389 --> 00:32:42.399 align:start position:0% storage um we've already seen everything 00:32:42.399 --> 00:32:47.310 align:start position:0% storage um we've already seen everything is<00:32:42.519> zero<00:32:43.159> initialized<00:32:44.159> we<00:32:44.320> can<00:32:44.760> trust<00:32:45.639> on<00:32:46.039> that 00:32:47.310 --> 00:32:47.320 align:start position:0% is zero initialized we can trust on that 00:32:47.320 --> 00:32:50.350 align:start position:0% is zero initialized we can trust on that and<00:32:48.320> Locker<00:32:48.760> variables<00:32:49.159> are<00:32:49.320> currently<00:32:49.919> used 00:32:50.350 --> 00:32:50.360 align:start position:0% and Locker variables are currently used 00:32:50.360 --> 00:32:52.430 align:start position:0% and Locker variables are currently used only<00:32:50.639> on<00:32:50.760> the<00:32:50.919> stack<00:32:51.360> so<00:32:51.519> it<00:32:51.639> doesn't<00:32:52.320> it 00:32:52.430 --> 00:32:52.440 align:start position:0% only on the stack so it doesn't it 00:32:52.440 --> 00:32:54.149 align:start position:0% only on the stack so it doesn't it doesn't<00:32:52.960> actually<00:32:53.240> use<00:32:53.480> memory<00:32:53.799> it<00:32:53.919> uses 00:32:54.149 --> 00:32:54.159 align:start position:0% doesn't actually use memory it uses 00:32:54.159 --> 00:32:57.430 align:start position:0% doesn't actually use memory it uses memory<00:32:54.480> only<00:32:54.880> for<00:32:55.880> op<00:32:56.159> codes<00:32:56.760> for<00:32:57.000> operations 00:32:57.430 --> 00:32:57.440 align:start position:0% memory only for op codes for operations 00:32:57.440 --> 00:32:59.070 align:start position:0% memory only for op codes for operations where<00:32:57.559> it's<00:32:58.120> really 00:32:59.070 --> 00:32:59.080 align:start position:0% where it's really 00:32:59.080 --> 00:33:03.070 align:start position:0% where it's really necessary<00:33:00.080> um<00:33:00.840> this<00:33:01.399> might<00:33:01.639> change<00:33:02.000> later 00:33:03.070 --> 00:33:03.080 align:start position:0% necessary um this might change later 00:33:03.080 --> 00:33:06.190 align:start position:0% necessary um this might change later because<00:33:04.080> the<00:33:04.200> evm<00:33:04.720> can<00:33:04.880> only<00:33:05.200> look 00:33:06.190 --> 00:33:06.200 align:start position:0% because the evm can only look 00:33:06.200 --> 00:33:10.549 align:start position:0% because the evm can only look at<00:33:07.200> at<00:33:07.360> the<00:33:08.000> stack<00:33:09.000> at<00:33:09.200> the<00:33:09.600> 16<00:33:10.080> topmost 00:33:10.549 --> 00:33:10.559 align:start position:0% at at the stack at the 16 topmost 00:33:10.559 --> 00:33:12.710 align:start position:0% at at the stack at the 16 topmost position<00:33:10.840> in<00:33:10.960> the<00:33:11.080> stack<00:33:11.399> so<00:33:11.760> if<00:33:12.240> we<00:33:12.360> have<00:33:12.519> many 00:33:12.710 --> 00:33:12.720 align:start position:0% position in the stack so if we have many 00:33:12.720 --> 00:33:14.629 align:start position:0% position in the stack so if we have many local<00:33:13.000> variables<00:33:13.519> or<00:33:13.880> very<00:33:14.080> complex 00:33:14.629 --> 00:33:14.639 align:start position:0% local variables or very complex 00:33:14.639 --> 00:33:17.070 align:start position:0% local variables or very complex expressions<00:33:15.639> and<00:33:15.760> we<00:33:15.919> want<00:33:16.039> to<00:33:16.679> store 00:33:17.070 --> 00:33:17.080 align:start position:0% expressions and we want to store 00:33:17.080 --> 00:33:19.230 align:start position:0% expressions and we want to store something<00:33:17.360> in<00:33:17.440> the<00:33:17.639> first<00:33:18.279> local<00:33:18.639> variable<00:33:19.120> we 00:33:19.230 --> 00:33:19.240 align:start position:0% something in the first local variable we 00:33:19.240 --> 00:33:20.710 align:start position:0% something in the first local variable we might<00:33:19.440> have<00:33:19.559> to<00:33:19.720> look<00:33:19.919> too<00:33:20.159> deep<00:33:20.360> into<00:33:20.559> the 00:33:20.710 --> 00:33:20.720 align:start position:0% might have to look too deep into the 00:33:20.720 --> 00:33:23.549 align:start position:0% might have to look too deep into the stack<00:33:21.519> so<00:33:22.080> we<00:33:22.240> have<00:33:22.360> to<00:33:22.720> copy<00:33:22.960> it<00:33:23.039> to<00:33:23.200> memory 00:33:23.549 --> 00:33:23.559 align:start position:0% stack so we have to copy it to memory 00:33:23.559 --> 00:33:26.470 align:start position:0% stack so we have to copy it to memory first<00:33:23.880> and<00:33:24.080> then<00:33:25.080> yeah<00:33:25.240> unwind<00:33:25.679> the<00:33:25.799> stack<00:33:26.159> and 00:33:26.470 --> 00:33:26.480 align:start position:0% first and then yeah unwind the stack and 00:33:26.480 --> 00:33:30.269 align:start position:0% first and then yeah unwind the stack and save<00:33:26.720> it<00:33:26.880> later<00:33:27.200> again 00:33:30.269 --> 00:33:30.279 align:start position:0% 00:33:30.279 --> 00:33:33.230 align:start position:0% um<00:33:31.279> the<00:33:31.519> storage<00:33:32.159> is<00:33:32.639> allocated<00:33:33.039> in<00:33:33.120> a 00:33:33.230 --> 00:33:33.240 align:start position:0% um the storage is allocated in a 00:33:33.240 --> 00:33:36.710 align:start position:0% um the storage is allocated in a continuous<00:33:33.799> way<00:33:34.200> so<00:33:34.799> uh<00:33:34.919> if<00:33:35.039> you<00:33:35.559> have<00:33:36.559> one 00:33:36.710 --> 00:33:36.720 align:start position:0% continuous way so uh if you have one 00:33:36.720 --> 00:33:39.070 align:start position:0% continuous way so uh if you have one struct<00:33:37.120> and<00:33:37.240> then<00:33:37.399> another<00:33:37.639> struct<00:33:38.120> then<00:33:38.919> they 00:33:39.070 --> 00:33:39.080 align:start position:0% struct and then another struct then they 00:33:39.080 --> 00:33:41.269 align:start position:0% struct and then another struct then they will<00:33:39.440> sit<00:33:39.799> direct<00:33:40.279> directly<00:33:40.679> next<00:33:40.919> to<00:33:41.080> each 00:33:41.269 --> 00:33:41.279 align:start position:0% will sit direct directly next to each 00:33:41.279 --> 00:33:42.950 align:start position:0% will sit direct directly next to each other<00:33:42.000> in 00:33:42.950 --> 00:33:42.960 align:start position:0% other in 00:33:42.960 --> 00:33:46.070 align:start position:0% other in storage<00:33:43.960> where<00:33:44.399> mappings<00:33:44.919> are<00:33:45.240> an<00:33:45.440> exception 00:33:46.070 --> 00:33:46.080 align:start position:0% storage where mappings are an exception 00:33:46.080 --> 00:33:50.710 align:start position:0% storage where mappings are an exception because<00:33:47.080> mappings<00:33:47.480> don't<00:33:47.679> have<00:33:47.760> a<00:33:48.240> size<00:33:49.240> so<00:33:50.120> uh 00:33:50.710 --> 00:33:50.720 align:start position:0% because mappings don't have a size so uh 00:33:50.720 --> 00:33:54.509 align:start position:0% because mappings don't have a size so uh to<00:33:50.919> compute<00:33:51.399> the<00:33:52.320> offset<00:33:53.039> of<00:33:53.159> a<00:33:53.320> mapping<00:33:54.279> you 00:33:54.509 --> 00:33:54.519 align:start position:0% to compute the offset of a mapping you 00:33:54.519 --> 00:33:57.870 align:start position:0% to compute the offset of a mapping you take<00:33:54.919> the<00:33:55.840> or<00:33:56.240> to<00:33:56.440> compute<00:33:56.799> the<00:33:57.200> offset<00:33:57.559> of<00:33:57.799> of 00:33:57.870 --> 00:33:57.880 align:start position:0% take the or to compute the offset of of 00:33:57.880 --> 00:34:00.590 align:start position:0% take the or to compute the offset of of a<00:33:58.080> value<00:33:58.639> in<00:33:58.760> the<00:33:58.919> mapping<00:33:59.760> you<00:33:59.960> take<00:34:00.200> the 00:34:00.590 --> 00:34:00.600 align:start position:0% a value in the mapping you take the 00:34:00.600 --> 00:34:04.269 align:start position:0% a value in the mapping you take the offset<00:34:01.039> of<00:34:01.159> the<00:34:01.480> mapping<00:34:02.480> concatenate<00:34:03.480> the 00:34:04.269 --> 00:34:04.279 align:start position:0% offset of the mapping concatenate the 00:34:04.279 --> 00:34:06.990 align:start position:0% offset of the mapping concatenate the key<00:34:05.279> compute<00:34:05.760> sha<00:34:06.120> three<00:34:06.320> of<00:34:06.480> that<00:34:06.600> and<00:34:06.760> that's 00:34:06.990 --> 00:34:07.000 align:start position:0% key compute sha three of that and that's 00:34:07.000 --> 00:34:09.710 align:start position:0% key compute sha three of that and that's the<00:34:07.200> the<00:34:07.320> offset<00:34:07.639> of<00:34:07.760> the<00:34:07.960> value<00:34:08.960> I<00:34:09.320> think 00:34:09.710 --> 00:34:09.720 align:start position:0% the the offset of the value I think 00:34:09.720 --> 00:34:11.310 align:start position:0% the the offset of the value I think that's<00:34:10.159> more<00:34:10.280> or<00:34:10.440> less<00:34:10.639> exactly<00:34:11.000> how<00:34:11.119> it's 00:34:11.310 --> 00:34:11.320 align:start position:0% that's more or less exactly how it's 00:34:11.320 --> 00:34:13.990 align:start position:0% that's more or less exactly how it's done<00:34:11.639> in<00:34:12.440> serpent<00:34:13.079> with<00:34:13.200> the<00:34:13.280> introduction<00:34:13.879> in 00:34:13.990 --> 00:34:14.000 align:start position:0% done in serpent with the introduction in 00:34:14.000 --> 00:34:14.869 align:start position:0% done in serpent with the introduction in serpent 00:34:14.869 --> 00:34:14.879 align:start position:0% serpent 00:34:14.879 --> 00:34:22.710 align:start position:0% serpent Cho<00:34:15.879> so<00:34:16.760> yeah<00:34:17.760> the<00:34:17.879> obvious<00:34:18.240> way<00:34:18.399> I<00:34:18.480> would<00:34:19.000> say 00:34:22.710 --> 00:34:22.720 align:start position:0% 00:34:22.720 --> 00:34:26.230 align:start position:0% um<00:34:23.720> okay<00:34:24.040> reference<00:34:24.399> to<00:34:24.560> other<00:34:24.800> contracts 00:34:26.230 --> 00:34:26.240 align:start position:0% um okay reference to other contracts 00:34:26.240 --> 00:34:29.109 align:start position:0% um okay reference to other contracts um<00:34:27.240> gav<00:34:27.480> already<00:34:27.879> gave<00:34:28.119> gave<00:34:28.240> an<00:34:28.399> example<00:34:28.879> for 00:34:29.109 --> 00:34:29.119 align:start position:0% um gav already gave gave an example for 00:34:29.119 --> 00:34:32.349 align:start position:0% um gav already gave gave an example for that<00:34:30.040> um<00:34:30.639> a<00:34:30.760> bit<00:34:30.919> more 00:34:32.349 --> 00:34:32.359 align:start position:0% that um a bit more 00:34:32.359 --> 00:34:36.069 align:start position:0% that um a bit more detailed<00:34:33.359> we<00:34:33.720> can<00:34:34.720> include<00:34:35.159> other<00:34:35.399> contract 00:34:36.069 --> 00:34:36.079 align:start position:0% detailed we can include other contract 00:34:36.079 --> 00:34:40.230 align:start position:0% detailed we can include other contract files<00:34:37.079> contract<00:34:37.399> source<00:34:37.720> files<00:34:38.679> and<00:34:39.679> yeah<00:34:39.919> use 00:34:40.230 --> 00:34:40.240 align:start position:0% files contract source files and yeah use 00:34:40.240 --> 00:34:43.030 align:start position:0% files contract source files and yeah use contracts<00:34:40.679> also<00:34:40.879> as<00:34:41.040> values<00:34:41.399> for<00:34:41.679> mappings<00:34:42.679> or 00:34:43.030 --> 00:34:43.040 align:start position:0% contracts also as values for mappings or 00:34:43.040 --> 00:34:45.389 align:start position:0% contracts also as values for mappings or directly<00:34:43.399> in 00:34:45.389 --> 00:34:45.399 align:start position:0% directly in 00:34:45.399 --> 00:34:50.550 align:start position:0% directly in storage<00:34:46.839> and<00:34:47.839> we<00:34:48.040> can<00:34:48.480> so<00:34:49.159> name<00:34:49.440> r<00:34:49.679> Adder<00:34:50.040> is<00:34:50.159> an 00:34:50.550 --> 00:34:50.560 align:start position:0% storage and we can so name r Adder is an 00:34:50.560 --> 00:34:53.030 align:start position:0% storage and we can so name r Adder is an address<00:34:51.560> we 00:34:53.030 --> 00:34:53.040 align:start position:0% address we 00:34:53.040 --> 00:34:55.550 align:start position:0% address we can<00:34:54.040> so<00:34:54.240> if<00:34:54.320> you<00:34:54.440> write<00:34:54.639> it<00:34:54.800> like<00:34:54.960> that<00:34:55.119> name<00:34:55.359> r 00:34:55.550 --> 00:34:55.560 align:start position:0% can so if you write it like that name r 00:34:55.560 --> 00:34:58.670 align:start position:0% can so if you write it like that name r is<00:34:55.800> is<00:34:55.960> a<00:34:56.240> is<00:34:56.359> a<00:34:56.480> contract<00:34:56.879> type<00:34:57.920> this<00:34:58.040> is<00:34:58.280> just 00:34:58.670 --> 00:34:58.680 align:start position:0% is is a is a contract type this is just 00:34:58.680 --> 00:35:02.349 align:start position:0% is is a is a contract type this is just uh<00:34:59.320> usual<00:34:59.800> type<00:35:00.040> conversion<00:35:00.839> so<00:35:01.839> address<00:35:02.240> can 00:35:02.349 --> 00:35:02.359 align:start position:0% uh usual type conversion so address can 00:35:02.359 --> 00:35:04.829 align:start position:0% uh usual type conversion so address can be<00:35:02.480> converted<00:35:02.839> to<00:35:02.960> a<00:35:03.079> contract<00:35:03.599> type<00:35:04.599> and<00:35:04.720> then 00:35:04.829 --> 00:35:04.839 align:start position:0% be converted to a contract type and then 00:35:04.839 --> 00:35:07.349 align:start position:0% be converted to a contract type and then we<00:35:05.000> store<00:35:05.200> it<00:35:05.320> in 00:35:07.349 --> 00:35:07.359 align:start position:0% we store it in 00:35:07.359 --> 00:35:10.829 align:start position:0% we store it in storage<00:35:08.560> um<00:35:09.560> we<00:35:09.720> can<00:35:10.040> from<00:35:10.240> this<00:35:10.400> point<00:35:10.560> on<00:35:10.760> we 00:35:10.829 --> 00:35:10.839 align:start position:0% storage um we can from this point on we 00:35:10.839 --> 00:35:12.550 align:start position:0% storage um we can from this point on we can<00:35:11.079> use<00:35:11.320> name<00:35:11.599> r<00:35:11.760> and<00:35:11.839> call<00:35:12.040> functions<00:35:12.359> on 00:35:12.550 --> 00:35:12.560 align:start position:0% can use name r and call functions on 00:35:12.560 --> 00:35:16.950 align:start position:0% can use name r and call functions on that<00:35:13.359> and<00:35:13.760> for<00:35:14.000> that<00:35:14.160> we<00:35:14.280> don't<00:35:14.560> need<00:35:15.000> the<00:35:16.000> full 00:35:16.950 --> 00:35:16.960 align:start position:0% that and for that we don't need the full 00:35:16.960 --> 00:35:19.030 align:start position:0% that and for that we don't need the full definition<00:35:17.400> of<00:35:17.520> the<00:35:17.640> name<00:35:18.040> contract<00:35:18.480> we<00:35:18.839> only 00:35:19.030 --> 00:35:19.040 align:start position:0% definition of the name contract we only 00:35:19.040 --> 00:35:21.030 align:start position:0% definition of the name contract we only need<00:35:19.160> to<00:35:19.280> know<00:35:19.440> its<00:35:19.599> interface<00:35:20.320> so<00:35:20.599> this<00:35:20.920> this 00:35:21.030 --> 00:35:21.040 align:start position:0% need to know its interface so this this 00:35:21.040 --> 00:35:23.630 align:start position:0% need to know its interface so this this name<00:35:21.520> s<00:35:22.079> file<00:35:22.800> can 00:35:23.630 --> 00:35:23.640 align:start position:0% name s file can 00:35:23.640 --> 00:35:26.829 align:start position:0% name s file can be<00:35:24.640> yeah<00:35:24.880> a<00:35:25.040> simple<00:35:25.480> file<00:35:25.880> which<00:35:26.440> has<00:35:26.599> all 00:35:26.829 --> 00:35:26.839 align:start position:0% be yeah a simple file which has all 00:35:26.839 --> 00:35:29.030 align:start position:0% be yeah a simple file which has all functions<00:35:27.359> but<00:35:27.760> not<00:35:27.920> the<00:35:28.040> function 00:35:29.030 --> 00:35:29.040 align:start position:0% functions but not the function 00:35:29.040 --> 00:35:32.750 align:start position:0% functions but not the function bodies<00:35:30.040> and<00:35:30.839> it's<00:35:31.040> different<00:35:31.440> for<00:35:32.200> this<00:35:32.440> line 00:35:32.750 --> 00:35:32.760 align:start position:0% bodies and it's different for this line 00:35:32.760 --> 00:35:35.829 align:start position:0% bodies and it's different for this line here<00:35:33.079> where<00:35:33.320> we<00:35:34.280> create<00:35:34.680> a<00:35:34.880> new<00:35:35.160> contract<00:35:35.680> and 00:35:35.829 --> 00:35:35.839 align:start position:0% here where we create a new contract and 00:35:35.839 --> 00:35:38.990 align:start position:0% here where we create a new contract and store<00:35:36.160> it<00:35:36.359> at<00:35:36.560> this<00:35:37.160> point<00:35:37.400> in<00:35:37.680> storage<00:35:38.680> so 00:35:38.990 --> 00:35:39.000 align:start position:0% store it at this point in storage so 00:35:39.000 --> 00:35:41.109 align:start position:0% store it at this point in storage so here<00:35:39.240> we<00:35:39.520> actually<00:35:39.839> need<00:35:40.320> the<00:35:40.599> the<00:35:40.760> full 00:35:41.109 --> 00:35:41.119 align:start position:0% here we actually need the the full 00:35:41.119 --> 00:35:44.870 align:start position:0% here we actually need the the full definition<00:35:41.520> of<00:35:41.640> the<00:35:41.760> coin<00:35:42.119> contract<00:35:43.119> to 00:35:44.870 --> 00:35:44.880 align:start position:0% definition of the coin contract to 00:35:44.880 --> 00:35:47.670 align:start position:0% definition of the coin contract to create<00:35:45.880> and<00:35:46.480> when<00:35:46.640> it's<00:35:46.800> stored<00:35:47.240> we<00:35:47.320> can<00:35:47.480> use 00:35:47.670 --> 00:35:47.680 align:start position:0% create and when it's stored we can use 00:35:47.680 --> 00:35:52.150 align:start position:0% create and when it's stored we can use it<00:35:47.839> to<00:35:48.359> call<00:35:48.599> a<00:35:48.760> function<00:35:49.560> send<00:35:50.480> amount<00:35:50.880> to<00:35:51.880> so 00:35:52.150 --> 00:35:52.160 align:start position:0% it to call a function send amount to so 00:35:52.160 --> 00:35:53.589 align:start position:0% it to call a function send amount to so that's<00:35:52.720> yeah<00:35:52.960> that's<00:35:53.079> the<00:35:53.200> function<00:35:53.440> we've 00:35:53.589 --> 00:35:53.599 align:start position:0% that's yeah that's the function we've 00:35:53.599 --> 00:35:59.270 align:start position:0% that's yeah that's the function we've seen<00:35:53.800> in<00:35:53.960> the<00:35:54.720> the<00:35:54.839> second<00:35:55.160> example 00:35:59.270 --> 00:35:59.280 align:start position:0% 00:35:59.280 --> 00:36:01.630 align:start position:0% okay<00:36:00.280> um 00:36:01.630 --> 00:36:01.640 align:start position:0% okay um 00:36:01.640 --> 00:36:05.950 align:start position:0% okay um yeah<00:36:02.640> what<00:36:02.880> are<00:36:03.200> the<00:36:03.440> plans<00:36:03.839> for<00:36:04.040> the<00:36:04.160> future 00:36:05.950 --> 00:36:05.960 align:start position:0% yeah what are the plans for the future 00:36:05.960 --> 00:36:09.829 align:start position:0% yeah what are the plans for the future um<00:36:06.960> I<00:36:07.079> think<00:36:07.280> we<00:36:07.400> will<00:36:07.640> have<00:36:07.920> a<00:36:08.680> complete<00:36:09.520> first 00:36:09.829 --> 00:36:09.839 align:start position:0% um I think we will have a complete first 00:36:09.839 --> 00:36:11.910 align:start position:0% um I think we will have a complete first usable<00:36:10.319> version<00:36:11.240> by<00:36:11.400> the<00:36:11.480> beginning<00:36:11.760> of 00:36:11.910 --> 00:36:11.920 align:start position:0% usable version by the beginning of 00:36:11.920 --> 00:36:14.710 align:start position:0% usable version by the beginning of December 00:36:14.710 --> 00:36:14.720 align:start position:0% December 00:36:14.720 --> 00:36:17.670 align:start position:0% December so<00:36:15.720> yeah<00:36:16.160> after<00:36:16.480> def<00:36:16.680> con 00:36:17.670 --> 00:36:17.680 align:start position:0% so yeah after def con 00:36:17.680 --> 00:36:21.069 align:start position:0% so yeah after def con zero<00:36:18.680> uh<00:36:18.960> the<00:36:19.119> current<00:36:19.520> state<00:36:19.920> is 00:36:21.069 --> 00:36:21.079 align:start position:0% zero uh the current state is 00:36:21.079 --> 00:36:23.270 align:start position:0% zero uh the current state is that<00:36:22.079> most<00:36:22.240> of<00:36:22.359> the<00:36:22.480> basic<00:36:22.720> features<00:36:23.040> are 00:36:23.270 --> 00:36:23.280 align:start position:0% that most of the basic features are 00:36:23.280 --> 00:36:26.390 align:start position:0% that most of the basic features are there<00:36:23.599> what<00:36:23.720> is<00:36:23.880> missing<00:36:24.599> is<00:36:25.599> actual<00:36:26.040> access 00:36:26.390 --> 00:36:26.400 align:start position:0% there what is missing is actual access 00:36:26.400 --> 00:36:30.630 align:start position:0% there what is missing is actual access to<00:36:26.760> the<00:36:26.920> blockchains<00:36:27.599> so<00:36:28.319> query<00:36:28.720> balances<00:36:29.640> and 00:36:30.630 --> 00:36:30.640 align:start position:0% to the blockchains so query balances and 00:36:30.640 --> 00:36:33.670 align:start position:0% to the blockchains so query balances and send<00:36:31.440> funds<00:36:32.440> and<00:36:32.720> references<00:36:33.280> to<00:36:33.480> other 00:36:33.670 --> 00:36:33.680 align:start position:0% send funds and references to other 00:36:33.680 --> 00:36:35.990 align:start position:0% send funds and references to other contracts<00:36:34.240> but<00:36:34.800> that's<00:36:35.200> not<00:36:35.480> much<00:36:35.720> work<00:36:35.920> I 00:36:35.990 --> 00:36:36.000 align:start position:0% contracts but that's not much work I 00:36:36.000 --> 00:36:38.829 align:start position:0% contracts but that's not much work I would<00:36:36.200> say 00:36:38.829 --> 00:36:38.839 align:start position:0% 00:36:38.839 --> 00:36:42.910 align:start position:0% so<00:36:39.839> future<00:36:40.200> areas<00:36:40.480> of<00:36:40.680> work<00:36:41.000> are<00:36:41.520> yeah<00:36:41.800> I<00:36:42.520> shall 00:36:42.910 --> 00:36:42.920 align:start position:0% so future areas of work are yeah I shall 00:36:42.920 --> 00:36:45.589 align:start position:0% so future areas of work are yeah I shall write<00:36:43.119> some<00:36:43.280> tutorials<00:36:44.000> or<00:36:44.359> actually<00:36:45.359> create 00:36:45.589 --> 00:36:45.599 align:start position:0% write some tutorials or actually create 00:36:45.599 --> 00:36:47.589 align:start position:0% write some tutorials or actually create a<00:36:45.760> specification<00:36:46.240> of<00:36:46.319> the<00:36:46.440> language<00:36:46.839> I 00:36:47.589 --> 00:36:47.599 align:start position:0% a specification of the language I 00:36:47.599 --> 00:36:49.910 align:start position:0% a specification of the language I think 00:36:49.910 --> 00:36:49.920 align:start position:0% think 00:36:49.920 --> 00:36:54.670 align:start position:0% think um<00:36:50.920> then<00:36:51.520> uh<00:36:52.359> depending<00:36:53.040> on<00:36:54.040> feedback<00:36:54.440> from 00:36:54.670 --> 00:36:54.680 align:start position:0% um then uh depending on feedback from 00:36:54.680 --> 00:36:57.630 align:start position:0% um then uh depending on feedback from users<00:36:55.680> we<00:36:55.880> might<00:36:56.160> add<00:36:56.319> some<00:36:56.560> new<00:36:56.960> features<00:36:57.319> to 00:36:57.630 --> 00:36:57.640 align:start position:0% users we might add some new features to 00:36:57.640 --> 00:36:58.270 align:start position:0% users we might add some new features to the 00:36:58.270 --> 00:36:58.280 align:start position:0% the 00:36:58.280 --> 00:37:00.550 align:start position:0% the language<00:36:59.280> we<00:36:59.520> might<00:36:59.760> need<00:36:59.920> to<00:37:00.079> improve<00:37:00.400> the 00:37:00.550 --> 00:37:00.560 align:start position:0% language we might need to improve the 00:37:00.560 --> 00:37:05.349 align:start position:0% language we might need to improve the optimizer<00:37:01.319> but<00:37:01.680> that<00:37:02.160> yeah<00:37:02.400> depends 00:37:05.349 --> 00:37:05.359 align:start position:0% 00:37:05.359 --> 00:37:08.470 align:start position:0% on<00:37:06.359> how<00:37:06.599> the<00:37:06.760> language<00:37:07.040> is<00:37:07.200> actually<00:37:07.480> used<00:37:08.160> so 00:37:08.470 --> 00:37:08.480 align:start position:0% on how the language is actually used so 00:37:08.480 --> 00:37:10.069 align:start position:0% on how the language is actually used so we<00:37:08.560> will<00:37:08.720> have<00:37:08.839> to<00:37:09.079> look<00:37:09.240> at<00:37:09.400> some<00:37:09.560> real<00:37:09.800> world 00:37:10.069 --> 00:37:10.079 align:start position:0% we will have to look at some real world 00:37:10.079 --> 00:37:11.069 align:start position:0% we will have to look at some real world example 00:37:11.069 --> 00:37:11.079 align:start position:0% example 00:37:11.079 --> 00:37:14.950 align:start position:0% example contracts<00:37:12.079> then<00:37:12.599> work<00:37:12.800> on<00:37:13.319> documentation<00:37:14.319> so 00:37:14.950 --> 00:37:14.960 align:start position:0% contracts then work on documentation so 00:37:14.960 --> 00:37:18.150 align:start position:0% contracts then work on documentation so this<00:37:15.960> netpc<00:37:16.560> documentation<00:37:17.160> where<00:37:17.319> the<00:37:17.440> next 00:37:18.150 --> 00:37:18.160 align:start position:0% this netpc documentation where the next 00:37:18.160 --> 00:37:19.470 align:start position:0% this netpc documentation where the next we'll<00:37:18.319> see<00:37:18.480> that<00:37:18.560> in<00:37:18.640> the<00:37:18.760> next 00:37:19.470 --> 00:37:19.480 align:start position:0% we'll see that in the next 00:37:19.480 --> 00:37:21.230 align:start position:0% we'll see that in the next talk 00:37:21.230 --> 00:37:21.240 align:start position:0% talk 00:37:21.240 --> 00:37:24.109 align:start position:0% talk and<00:37:22.240> actually<00:37:22.480> creating<00:37:22.960> the<00:37:23.240> the 00:37:24.109 --> 00:37:24.119 align:start position:0% and actually creating the the 00:37:24.119 --> 00:37:27.470 align:start position:0% and actually creating the the IDE<00:37:25.119> and<00:37:25.319> then<00:37:25.680> work<00:37:25.960> on<00:37:26.240> static<00:37:26.560> analysis<00:37:27.200> and 00:37:27.470 --> 00:37:27.480 align:start position:0% IDE and then work on static analysis and 00:37:27.480 --> 00:37:29.589 align:start position:0% IDE and then work on static analysis and formal<00:37:27.920> verification<00:37:28.920> and<00:37:29.079> of<00:37:29.200> course<00:37:29.400> bu 00:37:29.589 --> 00:37:29.599 align:start position:0% formal verification and of course bu 00:37:29.599 --> 00:37:30.630 align:start position:0% formal verification and of course bu fixes<00:37:29.880> and 00:37:30.630 --> 00:37:30.640 align:start position:0% fixes and 00:37:30.640 --> 00:37:34.950 align:start position:0% fixes and refactoring<00:37:31.640> that<00:37:31.760> can<00:37:31.960> always<00:37:32.160> be<00:37:32.560> done<00:37:33.960> um 00:37:34.950 --> 00:37:34.960 align:start position:0% refactoring that can always be done um 00:37:34.960 --> 00:37:38.109 align:start position:0% refactoring that can always be done um how<00:37:35.200> how<00:37:35.319> is<00:37:35.560> that<00:37:36.560> am<00:37:36.680> I<00:37:36.839> on<00:37:37.040> time 00:37:38.109 --> 00:37:38.119 align:start position:0% how how is that am I on time 00:37:38.119 --> 00:37:42.670 align:start position:0% how how is that am I on time or<00:37:39.200> okay<00:37:40.440> so<00:37:41.440> yeah<00:37:41.640> one<00:37:41.960> plan<00:37:42.319> language 00:37:42.670 --> 00:37:42.680 align:start position:0% or okay so yeah one plan language 00:37:42.680 --> 00:37:45.150 align:start position:0% or okay so yeah one plan language feature<00:37:43.240> I<00:37:43.319> don't<00:37:43.480> know<00:37:43.599> if<00:37:44.160> that's 00:37:45.150 --> 00:37:45.160 align:start position:0% feature I don't know if that's 00:37:45.160 --> 00:37:47.349 align:start position:0% feature I don't know if that's interesting<00:37:46.079> uh<00:37:46.240> Anonymous 00:37:47.349 --> 00:37:47.359 align:start position:0% interesting uh Anonymous 00:37:47.359 --> 00:37:50.109 align:start position:0% interesting uh Anonymous structs<00:37:48.359> so<00:37:48.720> you<00:37:48.839> can 00:37:50.109 --> 00:37:50.119 align:start position:0% structs so you can 00:37:50.119 --> 00:37:53.390 align:start position:0% structs so you can do<00:37:51.119> mappings<00:37:51.760> from<00:37:51.920> a<00:37:52.079> struct<00:37:52.520> type<00:37:52.960> without 00:37:53.390 --> 00:37:53.400 align:start position:0% do mappings from a struct type without 00:37:53.400 --> 00:37:57.950 align:start position:0% do mappings from a struct type without actually<00:37:54.160> creating<00:37:54.520> a<00:37:54.640> name<00:37:54.880> for<00:37:55.079> it<00:37:56.000> you<00:37:56.200> can 00:37:57.950 --> 00:37:57.960 align:start position:0% actually creating a name for it you can 00:37:57.960 --> 00:38:00.510 align:start position:0% actually creating a name for it you can so<00:37:58.359> functions<00:37:58.760> that<00:37:59.040> return<00:37:59.280> multiple<00:38:00.079> values 00:38:00.510 --> 00:38:00.520 align:start position:0% so functions that return multiple values 00:38:00.520 --> 00:38:01.829 align:start position:0% so functions that return multiple values you<00:38:00.599> can<00:38:00.760> just<00:38:00.880> store<00:38:01.200> them<00:38:01.359> in<00:38:01.560> local 00:38:01.829 --> 00:38:01.839 align:start position:0% you can just store them in local 00:38:01.839 --> 00:38:03.870 align:start position:0% you can just store them in local variables 00:38:03.870 --> 00:38:03.880 align:start position:0% variables 00:38:03.880 --> 00:38:06.990 align:start position:0% variables directly<00:38:04.880> and<00:38:05.079> also<00:38:05.400> return<00:38:05.640> them<00:38:05.839> like<00:38:06.040> that 00:38:06.990 --> 00:38:07.000 align:start position:0% directly and also return them like that 00:38:07.000 --> 00:38:08.550 align:start position:0% directly and also return them like that so<00:38:07.119> I<00:38:07.240> think<00:38:07.400> that's<00:38:07.560> something<00:38:08.040> we<00:38:08.200> want<00:38:08.440> but 00:38:08.550 --> 00:38:08.560 align:start position:0% so I think that's something we want but 00:38:08.560 --> 00:38:09.990 align:start position:0% so I think that's something we want but that's<00:38:08.680> not<00:38:08.839> implemented 00:38:09.990 --> 00:38:10.000 align:start position:0% that's not implemented 00:38:10.000 --> 00:38:14.230 align:start position:0% that's not implemented yet<00:38:11.400> um<00:38:12.400> some<00:38:12.599> ideas<00:38:12.880> for<00:38:13.040> the 00:38:14.230 --> 00:38:14.240 align:start position:0% yet um some ideas for the 00:38:14.240 --> 00:38:18.230 align:start position:0% yet um some ideas for the optimizer<00:38:15.240> I<00:38:15.359> think<00:38:15.640> it's<00:38:17.000> uh<00:38:18.000> really 00:38:18.230 --> 00:38:18.240 align:start position:0% optimizer I think it's uh really 00:38:18.240 --> 00:38:21.990 align:start position:0% optimizer I think it's uh really important<00:38:18.880> to<00:38:19.880> be<00:38:20.079> able<00:38:20.359> to<00:38:21.240> use<00:38:21.760> other 00:38:21.990 --> 00:38:22.000 align:start position:0% important to be able to use other 00:38:22.000 --> 00:38:25.390 align:start position:0% important to be able to use other contracts<00:38:22.680> as<00:38:23.200> Library<00:38:23.680> contracts<00:38:24.400> somehow 00:38:25.390 --> 00:38:25.400 align:start position:0% contracts as Library contracts somehow 00:38:25.400 --> 00:38:27.750 align:start position:0% contracts as Library contracts somehow at<00:38:25.520> least<00:38:25.760> for<00:38:26.599> simple<00:38:26.920> functions<00:38:27.280> like<00:38:27.560> like 00:38:27.750 --> 00:38:27.760 align:start position:0% at least for simple functions like like 00:38:27.760 --> 00:38:29.710 align:start position:0% at least for simple functions like like Computing<00:38:28.119> the<00:38:28.200> minimum<00:38:28.800> or<00:38:29.359> finding 00:38:29.710 --> 00:38:29.720 align:start position:0% Computing the minimum or finding 00:38:29.720 --> 00:38:33.349 align:start position:0% Computing the minimum or finding something<00:38:30.000> in<00:38:30.079> a<00:38:30.520> list<00:38:31.520> and<00:38:32.280> for<00:38:32.560> this<00:38:32.839> it's 00:38:33.349 --> 00:38:33.359 align:start position:0% something in a list and for this it's 00:38:33.359 --> 00:38:36.230 align:start position:0% something in a list and for this it's important<00:38:33.800> to<00:38:34.359> so<00:38:35.119> calls<00:38:35.480> to<00:38:35.640> other<00:38:35.800> functions 00:38:36.230 --> 00:38:36.240 align:start position:0% important to so calls to other functions 00:38:36.240 --> 00:38:38.309 align:start position:0% important to so calls to other functions are<00:38:36.720> quite<00:38:36.960> expensive<00:38:37.520> because<00:38:37.760> you<00:38:37.880> have<00:38:38.040> to 00:38:38.309 --> 00:38:38.319 align:start position:0% are quite expensive because you have to 00:38:38.319 --> 00:38:42.230 align:start position:0% are quite expensive because you have to move<00:38:38.599> all<00:38:38.839> arguments<00:38:39.240> to<00:38:39.760> memory<00:38:40.760> create<00:38:41.560> so 00:38:42.230 --> 00:38:42.240 align:start position:0% move all arguments to memory create so 00:38:42.240 --> 00:38:44.470 align:start position:0% move all arguments to memory create so run<00:38:42.560> this<00:38:42.760> this<00:38:42.920> call<00:38:43.160> up<00:38:43.319> code<00:38:43.760> and<00:38:43.960> then 00:38:44.470 --> 00:38:44.480 align:start position:0% run this this call up code and then 00:38:44.480 --> 00:38:47.910 align:start position:0% run this this call up code and then retrieve<00:38:44.880> them<00:38:45.000> from<00:38:45.200> memory<00:38:45.720> again<00:38:46.760> and<00:38:47.760> if 00:38:47.910 --> 00:38:47.920 align:start position:0% retrieve them from memory again and if 00:38:47.920 --> 00:38:49.790 align:start position:0% retrieve them from memory again and if the<00:38:48.040> function<00:38:48.359> is<00:38:48.640> small<00:38:49.079> then<00:38:49.240> it's<00:38:49.599> much 00:38:49.790 --> 00:38:49.800 align:start position:0% the function is small then it's much 00:38:49.800 --> 00:38:52.470 align:start position:0% the function is small then it's much more<00:38:50.119> efficient<00:38:50.480> to<00:38:50.720> just<00:38:51.280> copy<00:38:51.640> the<00:38:51.800> code<00:38:52.280> to 00:38:52.470 --> 00:38:52.480 align:start position:0% more efficient to just copy the code to 00:38:52.480 --> 00:38:54.309 align:start position:0% more efficient to just copy the code to the<00:38:52.640> to<00:38:52.800> that 00:38:54.309 --> 00:38:54.319 align:start position:0% the to that 00:38:54.319 --> 00:38:57.910 align:start position:0% the to that location<00:38:55.599> and<00:38:56.599> and<00:38:56.880> another<00:38:57.119> benefit<00:38:57.720> of 00:38:57.910 --> 00:38:57.920 align:start position:0% location and and another benefit of 00:38:57.920 --> 00:38:59.550 align:start position:0% location and and another benefit of inlining<00:38:58.319> function<00:38:58.560> causes<00:38:58.920> also<00:38:59.200> that<00:38:59.440> the 00:38:59.550 --> 00:38:59.560 align:start position:0% inlining function causes also that the 00:38:59.560 --> 00:39:00.990 align:start position:0% inlining function causes also that the the<00:38:59.680> optimizer<00:39:00.160> can<00:39:00.319> actually<00:39:00.560> optimize 00:39:00.990 --> 00:39:01.000 align:start position:0% the optimizer can actually optimize 00:39:01.000 --> 00:39:02.109 align:start position:0% the optimizer can actually optimize something 00:39:02.109 --> 00:39:02.119 align:start position:0% something 00:39:02.119 --> 00:39:05.470 align:start position:0% something there<00:39:03.119> then<00:39:03.440> it's<00:39:03.760> perhaps<00:39:04.040> necessary<00:39:04.400> to<00:39:04.880> to 00:39:05.470 --> 00:39:05.480 align:start position:0% there then it's perhaps necessary to to 00:39:05.480 --> 00:39:07.349 align:start position:0% there then it's perhaps necessary to to reorganize<00:39:06.040> the<00:39:06.160> local<00:39:06.359> Stacks<00:39:06.720> so<00:39:06.880> for 00:39:07.349 --> 00:39:07.359 align:start position:0% reorganize the local Stacks so for 00:39:07.359 --> 00:39:10.470 align:start position:0% reorganize the local Stacks so for example<00:39:08.359> if<00:39:08.880> two<00:39:09.160> V<00:39:09.400> two<00:39:09.560> local<00:39:09.880> variables<00:39:10.319> do 00:39:10.470 --> 00:39:10.480 align:start position:0% example if two V two local variables do 00:39:10.480 --> 00:39:12.190 align:start position:0% example if two V two local variables do not<00:39:10.680> really<00:39:10.920> overlap<00:39:11.480> in<00:39:11.599> a<00:39:11.720> function<00:39:12.079> they 00:39:12.190 --> 00:39:12.200 align:start position:0% not really overlap in a function they 00:39:12.200 --> 00:39:15.230 align:start position:0% not really overlap in a function they can<00:39:12.319> use<00:39:12.599> the<00:39:12.800> same<00:39:13.400> stack 00:39:15.230 --> 00:39:15.240 align:start position:0% can use the same stack 00:39:15.240 --> 00:39:19.309 align:start position:0% can use the same stack slot<00:39:16.400> and<00:39:17.400> if<00:39:17.880> the<00:39:18.000> feedback<00:39:18.480> results<00:39:18.960> in 00:39:19.309 --> 00:39:19.319 align:start position:0% slot and if the feedback results in 00:39:19.319 --> 00:39:21.790 align:start position:0% slot and if the feedback results in really<00:39:19.560> really<00:39:19.800> bad<00:39:20.440> performance<00:39:20.880> for<00:39:21.599> the 00:39:21.790 --> 00:39:21.800 align:start position:0% really really bad performance for the 00:39:21.800 --> 00:39:24.069 align:start position:0% really really bad performance for the compiler<00:39:22.800> then<00:39:22.960> it's<00:39:23.200> perhaps<00:39:23.520> necessary<00:39:23.880> to 00:39:24.069 --> 00:39:24.079 align:start position:0% compiler then it's perhaps necessary to 00:39:24.079 --> 00:39:26.309 align:start position:0% compiler then it's perhaps necessary to consider<00:39:24.440> some<00:39:25.240> yeah<00:39:25.400> simple<00:39:25.760> Intermediate 00:39:26.309 --> 00:39:26.319 align:start position:0% consider some yeah simple Intermediate 00:39:26.319 --> 00:39:27.990 align:start position:0% consider some yeah simple Intermediate Language<00:39:26.960> where 00:39:27.990 --> 00:39:28.000 align:start position:0% Language where 00:39:28.000 --> 00:39:29.829 align:start position:0% Language where more<00:39:28.240> optimizations<00:39:28.880> are<00:39:29.079> possible<00:39:29.440> than<00:39:29.599> on 00:39:29.829 --> 00:39:29.839 align:start position:0% more optimizations are possible than on 00:39:29.839 --> 00:39:34.630 align:start position:0% more optimizations are possible than on this<00:39:30.240> on<00:39:30.359> the<00:39:30.520> stack<00:39:30.760> based<00:39:31.040> evm 00:39:34.630 --> 00:39:34.640 align:start position:0% 00:39:34.640 --> 00:39:38.790 align:start position:0% code<00:39:35.880> um<00:39:36.920> so<00:39:37.920> some<00:39:38.119> ideas<00:39:38.359> for<00:39:38.520> static 00:39:38.790 --> 00:39:38.800 align:start position:0% code um so some ideas for static 00:39:38.800 --> 00:39:41.150 align:start position:0% code um so some ideas for static analysis 00:39:41.150 --> 00:39:41.160 align:start position:0% analysis 00:39:41.160 --> 00:39:43.430 align:start position:0% analysis um<00:39:42.160> con<00:39:42.480> functions<00:39:42.720> are<00:39:42.839> not<00:39:42.960> enforced 00:39:43.430 --> 00:39:43.440 align:start position:0% um con functions are not enforced 00:39:43.440 --> 00:39:46.870 align:start position:0% um con functions are not enforced currently<00:39:43.839> that<00:39:43.960> should<00:39:44.119> be<00:39:44.319> done<00:39:45.319> then<00:39:46.160> um 00:39:46.870 --> 00:39:46.880 align:start position:0% currently that should be done then um 00:39:46.880 --> 00:39:49.069 align:start position:0% currently that should be done then um what<00:39:47.000> is<00:39:47.200> also<00:39:47.680> quite<00:39:48.000> easy<00:39:48.319> I<00:39:48.440> think<00:39:48.720> without 00:39:49.069 --> 00:39:49.079 align:start position:0% what is also quite easy I think without 00:39:49.079 --> 00:39:51.870 align:start position:0% what is also quite easy I think without doing<00:39:49.440> the<00:39:49.599> whole<00:39:50.079> process<00:39:50.359> of<00:39:50.480> form<00:39:50.880> proofing 00:39:51.870 --> 00:39:51.880 align:start position:0% doing the whole process of form proofing 00:39:51.880 --> 00:39:54.510 align:start position:0% doing the whole process of form proofing is<00:39:52.079> to<00:39:52.880> determine<00:39:53.440> the<00:39:53.720> value<00:39:54.000> ranges<00:39:54.359> of 00:39:54.510 --> 00:39:54.520 align:start position:0% is to determine the value ranges of 00:39:54.520 --> 00:39:57.950 align:start position:0% is to determine the value ranges of local<00:39:55.200> variables<00:39:56.200> and<00:39:56.800> check<00:39:57.079> whether<00:39:57.760> some 00:39:57.950 --> 00:39:57.960 align:start position:0% local variables and check whether some 00:39:57.960 --> 00:40:01.390 align:start position:0% local variables and check whether some overflows<00:39:58.480> can<00:39:58.680> happen<00:39:59.160> so<00:40:00.160> if<00:40:00.440> some<00:40:00.960> addition 00:40:01.390 --> 00:40:01.400 align:start position:0% overflows can happen so if some addition 00:40:01.400 --> 00:40:04.109 align:start position:0% overflows can happen so if some addition was<00:40:01.599> protected<00:40:02.240> by<00:40:02.920> prior<00:40:03.520> prior<00:40:03.800> to<00:40:03.960> that 00:40:04.109 --> 00:40:04.119 align:start position:0% was protected by prior prior to that 00:40:04.119 --> 00:40:07.150 align:start position:0% was protected by prior prior to that checking<00:40:04.520> that<00:40:04.760> an<00:40:04.920> overflow<00:40:05.400> can<00:40:05.920> happen<00:40:06.920> and 00:40:07.150 --> 00:40:07.160 align:start position:0% checking that an overflow can happen and 00:40:07.160 --> 00:40:11.430 align:start position:0% checking that an overflow can happen and perhaps<00:40:07.920> also<00:40:08.920> checking<00:40:09.400> that<00:40:09.680> from<00:40:10.440> the 00:40:11.430 --> 00:40:11.440 align:start position:0% perhaps also checking that from the 00:40:11.440 --> 00:40:14.710 align:start position:0% perhaps also checking that from the value<00:40:11.880> range<00:40:12.880> some<00:40:13.720> equality<00:40:14.280> compar 00:40:14.710 --> 00:40:14.720 align:start position:0% value range some equality compar 00:40:14.720 --> 00:40:16.950 align:start position:0% value range some equality compar comparison<00:40:15.280> or<00:40:15.480> inequality<00:40:16.040> comparison<00:40:16.560> can 00:40:16.950 --> 00:40:16.960 align:start position:0% comparison or inequality comparison can 00:40:16.960 --> 00:40:21.150 align:start position:0% comparison or inequality comparison can never<00:40:17.240> be<00:40:17.400> true<00:40:17.839> and<00:40:18.079> then<00:40:19.079> we<00:40:19.480> see<00:40:19.880> that<00:40:20.880> the 00:40:21.150 --> 00:40:21.160 align:start position:0% never be true and then we see that the 00:40:21.160 --> 00:40:23.270 align:start position:0% never be true and then we see that the developer<00:40:21.599> did<00:40:21.760> some<00:40:21.880> error<00:40:22.240> there<00:40:22.440> so<00:40:23.040> some 00:40:23.270 --> 00:40:23.280 align:start position:0% developer did some error there so some 00:40:23.280 --> 00:40:25.630 align:start position:0% developer did some error there so some code<00:40:23.520> is<00:40:23.680> is<00:40:23.800> not<00:40:23.920> reachable<00:40:24.319> at 00:40:25.630 --> 00:40:25.640 align:start position:0% code is is not reachable at 00:40:25.640 --> 00:40:28.550 align:start position:0% code is is not reachable at all<00:40:26.640> um 00:40:28.550 --> 00:40:28.560 align:start position:0% all um 00:40:28.560 --> 00:40:30.510 align:start position:0% all um what<00:40:28.680> is<00:40:28.800> also<00:40:29.000> useful<00:40:29.359> I<00:40:29.480> think<00:40:29.720> is<00:40:30.000> to 00:40:30.510 --> 00:40:30.520 align:start position:0% what is also useful I think is to 00:40:30.520 --> 00:40:33.470 align:start position:0% what is also useful I think is to estimate<00:40:30.920> the<00:40:31.079> gas<00:40:31.319> usage<00:40:31.800> of<00:40:32.599> of<00:40:32.839> of<00:40:33.160> at<00:40:33.280> some 00:40:33.470 --> 00:40:33.480 align:start position:0% estimate the gas usage of of of at some 00:40:33.480 --> 00:40:36.270 align:start position:0% estimate the gas usage of of of at some Source<00:40:33.800> line<00:40:34.160> so<00:40:35.079> that<00:40:35.440> while<00:40:35.760> writing<00:40:36.079> a 00:40:36.270 --> 00:40:36.280 align:start position:0% Source line so that while writing a 00:40:36.280 --> 00:40:38.829 align:start position:0% Source line so that while writing a contract<00:40:37.280> you<00:40:37.520> actually<00:40:37.800> see<00:40:38.240> how<00:40:38.440> expensive 00:40:38.829 --> 00:40:38.839 align:start position:0% contract you actually see how expensive 00:40:38.839 --> 00:40:41.190 align:start position:0% contract you actually see how expensive the<00:40:39.000> line<00:40:39.280> is<00:40:39.599> and<00:40:39.880> you<00:40:40.160> can<00:40:40.720> perhaps<00:40:41.000> change 00:40:41.190 --> 00:40:41.200 align:start position:0% the line is and you can perhaps change 00:40:41.200 --> 00:40:43.630 align:start position:0% the line is and you can perhaps change it<00:40:41.319> to<00:40:41.480> be<00:40:42.119> less 00:40:43.630 --> 00:40:43.640 align:start position:0% it to be less 00:40:43.640 --> 00:40:45.670 align:start position:0% it to be less expensive 00:40:45.670 --> 00:40:45.680 align:start position:0% expensive 00:40:45.680 --> 00:40:50.750 align:start position:0% expensive and<00:40:46.680> what<00:40:47.200> we<00:40:47.400> probably<00:40:47.760> also<00:40:47.960> want<00:40:48.359> is<00:40:49.160> uh<00:40:49.400> if 00:40:50.750 --> 00:40:50.760 align:start position:0% and what we probably also want is uh if 00:40:50.760 --> 00:40:53.230 align:start position:0% and what we probably also want is uh if you<00:40:51.760> issue<00:40:52.040> a 00:40:53.230 --> 00:40:53.240 align:start position:0% you issue a 00:40:53.240 --> 00:40:56.430 align:start position:0% you issue a transaction<00:40:54.240> you<00:40:54.440> have<00:40:54.599> to<00:40:55.200> set<00:40:55.960> the<00:40:56.119> gas 00:40:56.430 --> 00:40:56.440 align:start position:0% transaction you have to set the gas 00:40:56.440 --> 00:40:59.270 align:start position:0% transaction you have to set the gas value<00:40:57.079> and<00:40:57.400> and<00:40:58.160> you<00:40:58.400> probably<00:40:58.720> want<00:40:58.839> to<00:40:59.079> have 00:40:59.270 --> 00:40:59.280 align:start position:0% value and and you probably want to have 00:40:59.280 --> 00:41:01.910 align:start position:0% value and and you probably want to have some<00:40:59.560> estimate<00:41:00.079> on<00:41:00.640> how<00:41:00.880> expensive<00:41:01.280> it<00:41:01.440> is 00:41:01.910 --> 00:41:01.920 align:start position:0% some estimate on how expensive it is 00:41:01.920 --> 00:41:03.670 align:start position:0% some estimate on how expensive it is some<00:41:02.480> lower<00:41:02.800> and<00:41:02.920> upper 00:41:03.670 --> 00:41:03.680 align:start position:0% some lower and upper 00:41:03.680 --> 00:41:08.390 align:start position:0% some lower and upper bound<00:41:04.960> um<00:41:05.960> this<00:41:06.160> of<00:41:06.599> course<00:41:07.599> will<00:41:07.839> in<00:41:07.960> the<00:41:08.079> end 00:41:08.390 --> 00:41:08.400 align:start position:0% bound um this of course will in the end 00:41:08.400 --> 00:41:10.430 align:start position:0% bound um this of course will in the end so<00:41:08.599> the<00:41:08.720> actual<00:41:09.040> gas<00:41:09.359> cost<00:41:09.680> will<00:41:09.880> in<00:41:10.000> the<00:41:10.119> end 00:41:10.430 --> 00:41:10.440 align:start position:0% so the actual gas cost will in the end 00:41:10.440 --> 00:41:12.950 align:start position:0% so the actual gas cost will in the end depend<00:41:10.720> on<00:41:10.960> the<00:41:11.119> order<00:41:11.720> transactions<00:41:12.280> are 00:41:12.950 --> 00:41:12.960 align:start position:0% depend on the order transactions are 00:41:12.960 --> 00:41:14.829 align:start position:0% depend on the order transactions are introduced<00:41:13.440> into<00:41:13.599> the<00:41:13.720> blockchain 00:41:14.829 --> 00:41:14.839 align:start position:0% introduced into the blockchain 00:41:14.839 --> 00:41:17.670 align:start position:0% introduced into the blockchain so<00:41:15.839> yeah<00:41:16.119> will<00:41:16.319> not 00:41:17.670 --> 00:41:17.680 align:start position:0% so yeah will not 00:41:17.680 --> 00:41:20.670 align:start position:0% so yeah will not be<00:41:18.680> uh<00:41:18.839> absolutely<00:41:19.319> correct<00:41:19.760> but<00:41:20.079> I<00:41:20.200> think 00:41:20.670 --> 00:41:20.680 align:start position:0% be uh absolutely correct but I think 00:41:20.680 --> 00:41:23.349 align:start position:0% be uh absolutely correct but I think it's<00:41:20.920> it's<00:41:21.480> so<00:41:21.760> we<00:41:21.880> can<00:41:22.119> provide<00:41:22.480> good<00:41:23.119> uh 00:41:23.349 --> 00:41:23.359 align:start position:0% it's it's so we can provide good uh 00:41:23.359 --> 00:41:27.710 align:start position:0% it's it's so we can provide good uh lower<00:41:23.640> and<00:41:23.760> upper<00:41:24.000> bonds<00:41:24.599> for<00:41:24.800> the<00:41:24.960> gas<00:41:25.160> usage 00:41:27.710 --> 00:41:27.720 align:start position:0% lower and upper bonds for the gas usage 00:41:27.720 --> 00:41:31.450 align:start position:0% lower and upper bonds for the gas usage okay<00:41:28.599> that's<00:41:28.839> it 00:41:31.450 --> 00:41:31.460 align:start position:0% okay that's it 00:41:31.460 --> 00:41:38.039 align:start position:0% okay that's it [Applause]