path: root/2023/info/repl-after.md

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<a name="repl-mainVideo-transcript"></a>
# Transcript


[[!template new="1" text="""Intro""" start="00:00:00.000" video="mainVideo-repl" id="subtitle"]]

[[!template text="""Hi, my name is Eduardo Ochs""" start="00:00:00.000" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and the title of this talk is""" start="00:00:00.015" video="mainVideo-repl" id="subtitle"]]
[[!template text="""REPLs in Strange Places: Lua, LaTeX,""" start="00:00:05.020" video="mainVideo-repl" id="subtitle"]]
[[!template text="""LPeg, LPegRex, and TikZ.""" start="00:00:07.840" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I'm the author of an Emacs package called eev,""" start="00:00:10.440" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and this is a talk at the EmacsConf 2023,""" start="00:00:13.400" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that is happening in December 2023 at the Internet.""" start="00:00:17.280" video="mainVideo-repl" id="subtitle"]]

[[!template new="1" text="""Diagrams""" start="00:00:21.560" video="mainVideo-repl" id="subtitle"]]

[[!template text="""This is one of the examples of diagrams""" start="00:00:21.560" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that we are going to see.""" start="00:00:24.244" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Let me show how I generated it.""" start="00:00:25.920" video="mainVideo-repl" id="subtitle"]]
[[!template text="""One second, I have to use a smaller font here.""" start="00:00:28.400" video="mainVideo-repl" id="subtitle"]]
[[!template text="""This is a file called parse32.lua.""" start="00:00:34.560" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Let me go back to this block of tests again.""" start="00:00:39.080" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Now, if I run this,""" start="00:00:42.600" video="mainVideo-repl" id="subtitle"]]
[[!template text="""we get these outputs here at the right.""" start="00:00:46.720" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Then in this line here,""" start="00:00:51.520" video="mainVideo-repl" id="subtitle"]]
[[!template text="""it generates a PDF,""" start="00:00:53.800" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and if I type `F8` here,""" start="00:00:55.420" video="mainVideo-repl" id="subtitle"]]
[[!template text="""it shows the PDF in the lower right window.""" start="00:00:57.780" video="mainVideo-repl" id="subtitle"]]

[[!template new="1" text="""eev""" start="00:01:03.320" video="mainVideo-repl" id="subtitle"]]

[[!template text="""Let me start by explaining briefly what is eev.""" start="00:01:03.320" video="mainVideo-repl" id="subtitle"]]
[[!template text="""First, it's something""" start="00:01:08.920" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that appeared by accident in the mid 90s.""" start="00:01:10.890" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I explained this story in my presentation at EmacsConf 2019.""" start="00:01:14.560" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It's an Emacs package that is part of ELPA.""" start="00:01:20.640" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It has at least 10 users.""" start="00:01:25.420" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Those are the ones that I know by name.""" start="00:01:28.720" video="mainVideo-repl" id="subtitle"]]
[[!template text="""eev means &quot;Emacs, execute verbosely&quot;.""" start="00:01:32.480" video="mainVideo-repl" id="subtitle"]]
[[!template text="""eev is something that treats eval-last-sexp""" start="00:01:36.960" video="mainVideo-repl" id="subtitle"]]
[[!template text="""as the central feature of Emacs.""" start="00:01:38.848" video="mainVideo-repl" id="subtitle"]]
[[!template text="""eev blurs the distinction between programmers and users,""" start="00:01:43.400" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and it replaces the slogan,""" start="00:01:47.280" video="mainVideo-repl" id="subtitle"]]
[[!template text="""&quot;users should not be forced to see Lisp&quot;""" start="00:01:49.960" video="mainVideo-repl" id="subtitle"]]
[[!template text="""(that is something that Richard Stallman told me once),""" start="00:01:52.360" video="mainVideo-repl" id="subtitle"]]
[[!template text="""by &quot;users should see Lisp instead of buttons,&quot;""" start="00:01:55.280" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and &quot;new users should see Lisp in the first five minutes.&quot;""" start="00:01:59.240" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I'm going to show some examples of that soon.""" start="00:02:03.400" video="mainVideo-repl" id="subtitle"]]
[[!template text="""eev uses code in the comments a lot""" start="00:02:08.160" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and also tests in comments.""" start="00:02:11.566" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I changed my way of presenting it,""" start="00:02:14.120" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and it became very REPL-centric""" start="00:02:16.782" video="mainVideo-repl" id="subtitle"]]
[[!template text="""in the last few years, in the sense that""" start="00:02:19.191" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I start by explaining its main features""" start="00:02:22.200" video="mainVideo-repl" id="subtitle"]]
[[!template text="""by its support for REPLs.""" start="00:02:26.461" video="mainVideo-repl" id="subtitle"]]
[[!template text="""eev supposes that we want to keep""" start="00:02:29.520" video="mainVideo-repl" id="subtitle"]]
[[!template text="""executable notes of everything.""" start="00:02:32.079" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I'm also going to show examples of this in a second.""" start="00:02:34.560" video="mainVideo-repl" id="subtitle"]]
[[!template text="""eev has lots of videos for people who hate videos,""" start="00:02:37.800" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and it tries to do everything""" start="00:02:42.120" video="mainVideo-repl" id="subtitle"]]
[[!template text="""with very little magic and without black boxes.""" start="00:02:44.271" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I'm going to explain many of these things very soon.""" start="00:02:47.640" video="mainVideo-repl" id="subtitle"]]

[[!template new="1" text="""Another figure""" start="00:02:51.360" video="mainVideo-repl" id="subtitle"]]

[[!template text="""This is a figure that I'm going to show in detail soon""" start="00:02:51.360" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that is about something important about Lua.""" start="00:02:58.200" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Oops, the font is very bad now,""" start="00:03:01.640" video="mainVideo-repl" id="subtitle"]]
[[!template text="""so let me change the font.""" start="00:03:03.400" video="mainVideo-repl" id="subtitle"]]
[[!template text="""The figure is this one.""" start="00:03:05.200" video="mainVideo-repl" id="subtitle"]]
[[!template text="""What most people do when they visit a file""" start="00:03:09.880" video="mainVideo-repl" id="subtitle"]]
[[!template text="""with something interesting in it,""" start="00:03:12.936" video="mainVideo-repl" id="subtitle"]]
[[!template text="""is that they just go there and they set a bookmark there,""" start="00:03:15.280" video="mainVideo-repl" id="subtitle"]]
[[!template text="""or they put the position in the register.""" start="00:03:18.360" video="mainVideo-repl" id="subtitle"]]
[[!template text="""But I prefer to keep links""" start="00:03:22.640" video="mainVideo-repl" id="subtitle"]]
[[!template text="""to everything that is interesting""" start="00:03:29.782" video="mainVideo-repl" id="subtitle"]]
[[!template text="""as an Elisp hyperlink.""" start="00:03:30.222" video="mainVideo-repl" id="subtitle"]]
[[!template text="""For example, this is an Elisp hyperlink to the file""" start="00:03:30.480" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that goes to this anchor here,""" start="00:03:34.237" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and to this string after this anchor.""" start="00:03:36.520" video="mainVideo-repl" id="subtitle"]]
[[!template text="""This is a variant that opens that file""" start="00:03:39.280" video="mainVideo-repl" id="subtitle"]]
[[!template text="""in the window at the right here,""" start="00:03:43.389" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and this is a sexp that changes the font.""" start="00:03:46.760" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I have a command with a very short name that does that,""" start="00:03:53.640" video="mainVideo-repl" id="subtitle"]]
[[!template text="""but I prefer to keep that as a one-liner.""" start="00:03:57.880" video="mainVideo-repl" id="subtitle"]]
[[!template text="""About the videos, we can see""" start="00:04:03.680" video="mainVideo-repl" id="subtitle"]]
[[!template text="""the list of first-class videos of eev by executing this,""" start="00:04:04.282" video="mainVideo-repl" id="subtitle"]]
[[!template text="""`M-x find-1stclassvideos`,""" start="00:04:11.440" video="mainVideo-repl" id="subtitle"]]
[[!template text="""or by running this alias here, `M-x 1c`,""" start="00:04:14.191" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and then what we see is this.""" start="00:04:18.480" video="mainVideo-repl" id="subtitle"]]
[[!template text="""The first sexp here regenerates this buffer,""" start="00:04:21.160" video="mainVideo-repl" id="subtitle"]]
[[!template text="""so we can make a mess here and then run this,""" start="00:04:25.560" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and the original buffer is regenerated again in a clean way.""" start="00:04:29.120" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Each of these things here""" start="00:04:34.120" video="mainVideo-repl" id="subtitle"]]
[[!template text="""opens a buffer with information about a video.""" start="00:04:36.952" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Let me take a specific example here.""" start="00:04:41.960" video="mainVideo-repl" id="subtitle"]]
[[!template text="""This video here is about one of the ancestors of this talk""" start="00:04:45.320" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that is a library that I wrote""" start="00:04:50.279" video="mainVideo-repl" id="subtitle"]]
[[!template text="""for creating diagrams in LaTeX""" start="00:04:52.800" video="mainVideo-repl" id="subtitle"]]
[[!template text="""using a package called [pict2e-lua] using REPLs.""" start="00:04:56.907" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Anyway, the thing is that if we run a sexp like this one""" start="00:05:03.000" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and we don't have a local copy of the video,""" start="00:05:10.029" video="mainVideo-repl" id="subtitle"]]
[[!template text="""eev will try to load the local copy""" start="00:05:16.315" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and instead of doing that by asking something""" start="00:05:19.582" video="mainVideo-repl" id="subtitle"]]
[[!template text="""like &quot;do you want me to download the local copy&quot;""" start="00:05:20.560" video="mainVideo-repl" id="subtitle"]]
[[!template text="""blah, blah, blah, it simply opens a buffer like this.""" start="00:05:25.382" video="mainVideo-repl" id="subtitle"]]
[[!template text="""And if we don't have a local copy yet,""" start="00:05:29.240" video="mainVideo-repl" id="subtitle"]]
[[!template text="""it will open a buffer like this one,""" start="00:05:35.515" video="mainVideo-repl" id="subtitle"]]
[[!template text="""in which these things here in comments""" start="00:05:37.221" video="mainVideo-repl" id="subtitle"]]
[[!template text="""are links to the documentation.""" start="00:05:40.031" video="mainVideo-repl" id="subtitle"]]
[[!template text="""This thing here explains the idea""" start="00:05:42.679" video="mainVideo-repl" id="subtitle"]]
[[!template text="""of local copies of files from the internet.""" start="00:05:45.781" video="mainVideo-repl" id="subtitle"]]
[[!template text="""There are more details here and here,""" start="00:05:50.279" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and this is a script that we can execute line by line.""" start="00:05:54.121" video="mainVideo-repl" id="subtitle"]]
[[!template text="""So instead of this script being hidden behind the button""" start="00:05:59.580" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that we just press after a question""" start="00:06:04.277" video="mainVideo-repl" id="subtitle"]]
[[!template text="""like &quot;do you want me to do something,&quot; blah, blah, blah,""" start="00:06:07.160" video="mainVideo-repl" id="subtitle"]]
[[!template text="""&quot;yes or no?&quot;, the script is visible here""" start="00:06:10.709" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and we can execute it step by step.""" start="00:06:13.229" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It creates a terminal with a shell here in the right window""" start="00:06:15.380" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and when we type `F8` in these lines here,""" start="00:06:22.458" video="mainVideo-repl" id="subtitle"]]
[[!template text="""the lines are sent to this line.""" start="00:06:26.989" video="mainVideo-repl" id="subtitle"]]
[[!template text="""So this is going to download a copy of the video,""" start="00:06:30.360" video="mainVideo-repl" id="subtitle"]]
[[!template text="""the wget says that I already have a copy of the video""" start="00:06:33.843" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and its subtitles and so on.""" start="00:06:38.135" video="mainVideo-repl" id="subtitle"]]
[[!template text="""And after getting a copy of the video""" start="00:06:40.360" video="mainVideo-repl" id="subtitle"]]
[[!template text="""we can run this exp here and it displays the video.""" start="00:06:45.740" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I said that eev has lots of videos""" start="00:06:52.960" video="mainVideo-repl" id="subtitle"]]
[[!template text="""for people who hate videos.""" start="00:06:55.487" video="mainVideo-repl" id="subtitle"]]
[[!template text="""The idea is that very few people""" start="00:06:57.436" video="mainVideo-repl" id="subtitle"]]
[[!template text="""are going to watch the videos in real time.""" start="00:07:00.047" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Most of the people that I know, or most of the people""" start="00:07:03.082" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that are interested in eev in some way,""" start="00:07:07.643" video="mainVideo-repl" id="subtitle"]]
[[!template text="""they are going to watch just small sections of the video.""" start="00:07:10.791" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Most of the time, they are just going to""" start="00:07:14.321" video="mainVideo-repl" id="subtitle"]]
[[!template text="""read the subtitles of the video.""" start="00:07:17.575" video="mainVideo-repl" id="subtitle"]]
[[!template text="""For each one of the videos""" start="00:07:19.940" video="mainVideo-repl" id="subtitle"]]
[[!template text="""we have a page about the video...""" start="00:07:22.532" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Let me see if I have internet here...""" start="00:07:25.296" video="mainVideo-repl" id="subtitle"]]
[[!template text="""This is a page. Usually these pages""" start="00:07:29.674" video="mainVideo-repl" id="subtitle"]]
[[!template text="""have a link to another page,""" start="00:07:34.902" video="mainVideo-repl" id="subtitle"]]
[[!template text="""the page that has all the subtitles of the video,""" start="00:07:38.428" video="mainVideo-repl" id="subtitle"]]
[[!template text="""wherever. In this one, it's not so visible.""" start="00:07:43.891" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Anyway, there are several ways of accessing""" start="00:07:48.588" video="mainVideo-repl" id="subtitle"]]
[[!template text="""the subtitles of the video.""" start="00:07:52.002" video="mainVideo-repl" id="subtitle"]]
[[!template text="""One of the ways is by running this sexp here""" start="00:07:53.964" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that opens a file in Lua.""" start="00:07:58.633" video="mainVideo-repl" id="subtitle"]]
[[!template text="""That is what I use to generate the subtitles.""" start="00:08:01.065" video="mainVideo-repl" id="subtitle"]]
[[!template text="""By the way, each one of these things here""" start="00:08:05.440" video="mainVideo-repl" id="subtitle"]]
[[!template text="""is hyperlinked to a position of the video.""" start="00:08:10.369" video="mainVideo-repl" id="subtitle"]]
[[!template text="""If I type this, it goes to that position.""" start="00:08:14.680" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Anyway, let me go back.""" start="00:08:21.281" video="mainVideo-repl" id="subtitle"]]
[[!template text="""So the tutorials of eev, the intros of eev""" start="00:08:24.580" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that start with `find-` and end with `-intro`,""" start="00:08:28.558" video="mainVideo-repl" id="subtitle"]]
[[!template text="""they have lots of blocks that say""" start="00:08:32.351" video="mainVideo-repl" id="subtitle"]]
[[!template text="""video links like this one.""" start="00:08:35.333" video="mainVideo-repl" id="subtitle"]]
[[!template text="""These blocks have links to positions in videos.""" start="00:08:37.613" video="mainVideo-repl" id="subtitle"]]
[[!template text="""If we don't have a local copy of the video yet,""" start="00:08:41.973" video="mainVideo-repl" id="subtitle"]]
[[!template text="""the thing shows us a script""" start="00:08:46.333" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that lets us download the local copy.""" start="00:08:49.016" video="mainVideo-repl" id="subtitle"]]

[[!template new="1" text="""eev-wconfig, magic, and black boxes""" start="00:08:52.560" video="mainVideo-repl" id="subtitle"]]

[[!template text="""I said that I was going to explain""" start="00:08:52.560" video="mainVideo-repl" id="subtitle"]]
[[!template text="""what I mean by magic and black boxes,""" start="00:08:57.441" video="mainVideo-repl" id="subtitle"]]
[[!template text="""this is something that I've been trying""" start="00:09:01.856" video="mainVideo-repl" id="subtitle"]]
[[!template text="""to explain for a long time""" start="00:09:03.800" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and I think that I got a very good explanation about that""" start="00:09:05.112" video="mainVideo-repl" id="subtitle"]]
[[!template text="""in a video that I made about something called eev-wconfig""" start="00:09:08.762" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that is a tool for configuring eev on Windows without magic,""" start="00:09:12.349" video="mainVideo-repl" id="subtitle"]]
[[!template text="""without buttons that do things,""" start="00:09:17.944" video="mainVideo-repl" id="subtitle"]]
[[!template text="""without explaining what they are doing.""" start="00:09:20.879" video="mainVideo-repl" id="subtitle"]]
[[!template text="""This is a part of the subtitles of the video.""" start="00:09:24.380" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Let me read that.""" start="00:09:28.079" video="mainVideo-repl" id="subtitle"]]
[[!template text="""eev-wconfig is an attempt to solve the problem""" start="00:09:29.446" video="mainVideo-repl" id="subtitle"]]
[[!template text="""of how to install these things on Windows""" start="00:09:32.532" video="mainVideo-repl" id="subtitle"]]
[[!template text="""both without magic and with very little magic.""" start="00:09:35.350" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Remember this slogan: &quot;Any sufficiently advanced technology""" start="00:09:40.040" video="mainVideo-repl" id="subtitle"]]
[[!template text="""is indistinguishable from magic.&quot;""" start="00:09:44.942" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Here in this video I'm going to use the term magic""" start="00:09:47.600" video="mainVideo-repl" id="subtitle"]]
[[!template text="""as a shorthand for sufficiently advanced technology""" start="00:09:51.434" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that is something that is complex and non obvious""" start="00:09:55.263" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and that is indistinguishable from magic""" start="00:09:58.945" video="mainVideo-repl" id="subtitle"]]
[[!template text="""in the sense of being almost impossible to understand.""" start="00:10:01.921" video="mainVideo-repl" id="subtitle"]]
[[!template text="""And I'm also going to use the term black box""" start="00:10:05.840" video="mainVideo-repl" id="subtitle"]]
[[!template text="""as a near synonym for magic""" start="00:10:09.273" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and sometimes the term black box is more convenient""" start="00:10:11.409" video="mainVideo-repl" id="subtitle"]]
[[!template text="""even though it's a bit longer,""" start="00:10:15.218" video="mainVideo-repl" id="subtitle"]]
[[!template text="""it has more letters because when I use the term black box""" start="00:10:17.489" video="mainVideo-repl" id="subtitle"]]
[[!template text="""it invites us to use expressions""" start="00:10:21.334" video="mainVideo-repl" id="subtitle"]]
[[!template text="""like opening the black box""" start="00:10:23.522" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and I'm going to use that expression a lot.""" start="00:10:27.873" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Now let me try to explain what is. Sorry,""" start="00:10:34.800" video="mainVideo-repl" id="subtitle"]]
[[!template text="""let me change the font.""" start="00:10:40.900" video="mainVideo-repl" id="subtitle"]]

[[!template new="1" text="""Lua""" start="00:10:44.240" video="mainVideo-repl" id="subtitle"]]

[[!template text="""What is Lua?""" start="00:10:44.240" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Lua is a minimalistic language""" start="00:10:45.240" video="mainVideo-repl" id="subtitle"]]
[[!template text="""in the sense of battery is not included.""" start="00:10:48.646" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It uses associative tables for most of its data structures.""" start="00:10:53.040" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It's so minimalistic""" start="00:10:57.988" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that the default print function""" start="00:11:00.875" video="mainVideo-repl" id="subtitle"]]
[[!template text="""when we create an associative table and we ask it to print--""" start="00:11:05.148" video="mainVideo-repl" id="subtitle"]]
[[!template text="""we ask print to print an associative table--""" start="00:11:11.960" video="mainVideo-repl" id="subtitle"]]
[[!template text="""it just prints the address of the table.""" start="00:11:14.915" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Here are some examples. Here is a table""" start="00:11:17.600" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and when we ask to print it,""" start="00:11:20.903" video="mainVideo-repl" id="subtitle"]]
[[!template text="""it just says that it's the table at this address here.""" start="00:11:23.297" video="mainVideo-repl" id="subtitle"]]
[[!template text="""One of the things that most people do""" start="00:11:28.200" video="mainVideo-repl" id="subtitle"]]
[[!template text="""when they start using Lua is that either""" start="00:11:30.894" video="mainVideo-repl" id="subtitle"]]
[[!template text="""they download a package with a print to printing function""" start="00:11:33.587" video="mainVideo-repl" id="subtitle"]]
[[!template text="""or they write their own print to printing functions.""" start="00:11:36.314" video="mainVideo-repl" id="subtitle"]]
[[!template text="""My own print to printing function""" start="00:11:39.520" video="mainVideo-repl" id="subtitle"]]
[[!template text="""is called PP with upper case letters,""" start="00:11:41.976" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and it works like this.""" start="00:11:44.451" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It prints associative tables in a way like this.""" start="00:11:46.758" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It says that for the key 1,""" start="00:11:52.073" video="mainVideo-repl" id="subtitle"]]
[[!template text="""the value associated to it is 2;""" start="00:11:54.126" video="mainVideo-repl" id="subtitle"]]
[[!template text="""for the key 2, the value is 3;""" start="00:11:56.603" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and for the key 3, the value is 5.""" start="00:11:59.079" video="mainVideo-repl" id="subtitle"]]
[[!template text="""When I started using Lua, one of my favorite languages""" start="00:12:09.240" video="mainVideo-repl" id="subtitle"]]
[[!template text="""was also a language that used associative tables a lot.""" start="00:12:12.380" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It was called Icon. I had to write my own""" start="00:12:16.624" video="mainVideo-repl" id="subtitle"]]
[[!template text="""print to printing functions for Icon,""" start="00:12:20.340" video="mainVideo-repl" id="subtitle"]]
[[!template text="""so I just had to port my print to printing functions to Lua.""" start="00:12:23.395" video="mainVideo-repl" id="subtitle"]]
[[!template text="""My first version looked something like this.""" start="00:12:29.426" video="mainVideo-repl" id="subtitle"]]
[[!template text="""it just had some global functions. Lots of them actually.""" start="00:12:34.351" video="mainVideo-repl" id="subtitle"]]
[[!template text="""After a while, I rewrote it.""" start="00:12:40.080" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I rewrote it again and again and again.""" start="00:12:41.934" video="mainVideo-repl" id="subtitle"]]
[[!template text="""This is one of the versions""" start="00:12:44.504" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that is not even the default at this point.""" start="00:12:48.398" video="mainVideo-repl" id="subtitle"]]
[[!template text="""`tos` is for to string. This is a demo.""" start="00:12:53.752" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It's very modular, so it's easy to replace parts of it""" start="00:12:57.703" video="mainVideo-repl" id="subtitle"]]
[[!template text="""or to toggle flags. This is an example.""" start="00:13:02.906" video="mainVideo-repl" id="subtitle"]]
[[!template text="""If I try to print the table of methods for a certain class--""" start="00:13:06.568" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I only need a smaller font--it prints the table like this""" start="00:13:11.798" video="mainVideo-repl" id="subtitle"]]
[[!template text="""with the names of the methods""" start="00:13:16.246" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and then links to the source code of the functions.""" start="00:13:18.511" video="mainVideo-repl" id="subtitle"]]
[[!template text="""These links only make sense in Emacs and in eev.""" start="00:13:22.360" video="mainVideo-repl" id="subtitle"]]
[[!template text="""When we run a link like this one,""" start="00:13:26.672" video="mainVideo-repl" id="subtitle"]]
[[!template text="""it shows the source code and the window at the right.""" start="00:13:30.297" video="mainVideo-repl" id="subtitle"]]
[[!template text="""For some functions, the source code is three lines.""" start="00:13:34.014" video="mainVideo-repl" id="subtitle"]]
[[!template text="""For other ones, it's one line and whatever.""" start="00:13:38.648" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Anyway, let me go back.""" start="00:13:42.320" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Lua can be used in many different styles.""" start="00:13:44.150" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Most people hate other people's styles.""" start="00:13:47.491" video="mainVideo-repl" id="subtitle"]]
[[!template text="""When I started using it in the year 2000,""" start="00:13:52.240" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I learned most of the basic language in a single day.""" start="00:13:55.253" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It was very similar to things that I was already using.""" start="00:13:59.567" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Then I rewrote the mini language""" start="00:14:04.043" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that I was using to generate the HTML for my pages in Lua.""" start="00:14:08.389" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Actually, I had to rewrite it many times""" start="00:14:15.200" video="mainVideo-repl" id="subtitle"]]
[[!template text="""but the first version I certainly did""" start="00:14:17.592" video="mainVideo-repl" id="subtitle"]]
[[!template text="""in my first weeks or first months using Lua.""" start="00:14:21.368" video="mainVideo-repl" id="subtitle"]]
[[!template text="""In the beginning, I was just using it for writing programs""" start="00:14:25.740" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that either didn't take any input at all""" start="00:14:29.654" video="mainVideo-repl" id="subtitle"]]
[[!template text="""because the input was already in the source file,""" start="00:14:32.877" video="mainVideo-repl" id="subtitle"]]
[[!template text="""or that worked as a Unix function:""" start="00:14:36.728" video="mainVideo-repl" id="subtitle"]]
[[!template text="""the Unix programs that would read files,""" start="00:14:39.400" video="mainVideo-repl" id="subtitle"]]
[[!template text="""process these files in some way, and output something.""" start="00:14:42.452" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I mentioned the basic language here,""" start="00:14:49.560" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I only learned how to use closures, meta tables,""" start="00:14:52.201" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and coroutines many years later.""" start="00:14:55.626" video="mainVideo-repl" id="subtitle"]]
[[!template text="""In the beginning when I started using Lua""" start="00:15:00.600" video="mainVideo-repl" id="subtitle"]]
[[!template text="""it didn't have a package manager.""" start="00:15:02.589" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It appeared later. It is called luarocks.""" start="00:15:04.200" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It has had this package manager for several years.""" start="00:15:08.300" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Most of the rocks for luarocks are poorly documented""" start="00:15:13.180" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and hacker-unfriendly.""" start="00:15:17.243" video="mainVideo-repl" id="subtitle"]]
[[!template text="""You can't rely just on the documentation.""" start="00:15:18.898" video="mainVideo-repl" id="subtitle"]]
[[!template text="""You can't rely just on the source code,""" start="00:15:22.080" video="mainVideo-repl" id="subtitle"]]
[[!template text="""because--I mean, if you're a genius, of course you can,""" start="00:15:25.189" video="mainVideo-repl" id="subtitle"]]
[[!template text="""but for people who are either""" start="00:15:28.707" video="mainVideo-repl" id="subtitle"]]
[[!template text="""lazy or dumb or whatever like me, or unfocused,""" start="00:15:31.545" video="mainVideo-repl" id="subtitle"]]
[[!template text="""the source code is hard to understand""" start="00:15:35.896" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and hard to tinker with.""" start="00:15:39.491" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Some rocks are excellent.""" start="00:15:41.760" video="mainVideo-repl" id="subtitle"]]
[[!template text="""The best rocks are well documented,""" start="00:15:43.761" video="mainVideo-repl" id="subtitle"]]
[[!template text="""but they are hacker-unfriendly""" start="00:15:46.453" video="mainVideo-repl" id="subtitle"]]
[[!template text="""in the sense that I hope that I'll be able to explain soon.""" start="00:15:48.760" video="mainVideo-repl" id="subtitle"]]
[[!template text="""The best rocks use local variables and meta tables a lot,""" start="00:15:53.640" video="mainVideo-repl" id="subtitle"]]
[[!template text="""so if you are a beginner learning Lua""" start="00:15:59.467" video="mainVideo-repl" id="subtitle"]]
[[!template text="""you're not going to understand what their source codes do.""" start="00:16:02.906" video="mainVideo-repl" id="subtitle"]]
[[!template text="""They use lots of dirty tricks.""" start="00:16:08.246" video="mainVideo-repl" id="subtitle"]]

[[!template new="1" text="""Object orientation in Lua""" start="00:16:10.960" video="mainVideo-repl" id="subtitle"]]

[[!template text="""Let me talk a bit about object orientation in Lua.""" start="00:16:10.960" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It can be done in many ways. The main book about Lua""" start="00:16:14.360" video="mainVideo-repl" id="subtitle"]]
[[!template text="""called Programming in Lua""" start="00:16:18.276" video="mainVideo-repl" id="subtitle"]]
[[!template text="""by one of the authors of the language""" start="00:16:20.141" video="mainVideo-repl" id="subtitle"]]
[[!template text="""called Roberto Ierusalimschy""" start="00:16:22.866" video="mainVideo-repl" id="subtitle"]]
[[!template text="""presents several ways of doing object orientation in Lua.""" start="00:16:24.730" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I hated all of these ways,""" start="00:16:28.680" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and also the ways that I tried from the rocks.""" start="00:16:31.387" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Then I wrote my own way""" start="00:16:36.057" video="mainVideo-repl" id="subtitle"]]
[[!template text="""of doing object orientation in Lua.""" start="00:16:37.934" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It's very minimalistic. It's in this file here eoo.lua.""" start="00:16:40.348" video="mainVideo-repl" id="subtitle"]]
[[!template text="""The main code is just these five lines here.""" start="00:16:45.654" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Here's an example of how it works.""" start="00:16:49.899" video="mainVideo-repl" id="subtitle"]]
[[!template text="""We define a class vector with some meta methods.""" start="00:16:56.400" video="mainVideo-repl" id="subtitle"]]
[[!template text="""This meta method here will tell Lua""" start="00:17:03.002" video="mainVideo-repl" id="subtitle"]]
[[!template text="""what to do when the user asks to add two vectors.""" start="00:17:06.295" video="mainVideo-repl" id="subtitle"]]
[[!template text="""This one here tells Lua what to do""" start="00:17:10.868" video="mainVideo-repl" id="subtitle"]]
[[!template text="""when the user asks Lua to convert a vector to a string""" start="00:17:13.987" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and whatever. This one is something""" start="00:17:18.889" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that I'm going to explain in a second.""" start="00:17:22.008" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Here we create a vector""" start="00:17:25.580" video="mainVideo-repl" id="subtitle"]]
[[!template text="""with these coordinates 3 and 4.""" start="00:17:25.580" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Here we create another vector.""" start="00:17:25.581" video="mainVideo-repl" id="subtitle"]]
[[!template text="""If we print here,""" start="00:17:31.600" video="mainVideo-repl" id="subtitle"]]
[[!template text="""then Lua uses the function here in the `__tostring`.""" start="00:17:33.031" video="mainVideo-repl" id="subtitle"]]
[[!template text="""If we add two vectors""" start="00:17:37.154" video="mainVideo-repl" id="subtitle"]]
[[!template text="""it uses the function here in the `__add` meta method.""" start="00:17:38.908" video="mainVideo-repl" id="subtitle"]]
[[!template text="""If we run the method `norm`,""" start="00:17:42.654" video="mainVideo-repl" id="subtitle"]]
[[!template text="""it is defined here in the table index.""" start="00:17:45.045" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Anyway, even with this thing being so small,""" start="00:17:51.680" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I used to forget how it works all the time.""" start="00:17:57.676" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Actually, I always forget how things work,""" start="00:18:04.618" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and I have to remember them somehow.""" start="00:18:08.201" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I have to have tricks for remembering,""" start="00:18:11.348" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and tricks for summarizing things and diagrams, and so on.""" start="00:18:14.921" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Every time that I forgot how this thing worked,""" start="00:18:19.770" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I went back to the source code""" start="00:18:23.310" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and then I looked at the diagrams,""" start="00:18:25.461" video="mainVideo-repl" id="subtitle"]]
[[!template text="""or, of course, the first time,""" start="00:18:28.149" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I had to draw the diagrams. I run the examples.""" start="00:18:30.995" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Of course, in the beginning""" start="00:18:33.801" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I thought that the code was clear.""" start="00:18:35.540" video="mainVideo-repl" id="subtitle"]]
[[!template text="""My examples were very brief.""" start="00:18:37.504" video="mainVideo-repl" id="subtitle"]]
[[!template text="""So I had to rewrite the examples many times""" start="00:18:39.738" video="mainVideo-repl" id="subtitle"]]
[[!template text="""until they became let's say perfect.""" start="00:18:43.566" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I was saying that Lua can be used in many ways""" start="00:18:50.880" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and in my way of using Lua, in my favorite way,""" start="00:18:54.091" video="mainVideo-repl" id="subtitle"]]
[[!template text="""everything can be inspected and modified from REPLs""" start="00:18:58.404" video="mainVideo-repl" id="subtitle"]]
[[!template text="""like we can do in Emacs and in SmallTalk, sort of.""" start="00:19:03.076" video="mainVideo-repl" id="subtitle"]]
[[!template text="""In my favorite way of using Lua""" start="00:19:06.818" video="mainVideo-repl" id="subtitle"]]
[[!template text="""there's no security at all.""" start="00:19:09.437" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Everything can be changed at all times.""" start="00:19:11.532" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Of course, most people hate that.""" start="00:19:17.460" video="mainVideo-repl" id="subtitle"]]

[[!template new="1" text="""My init file""" start="00:19:19.823" video="mainVideo-repl" id="subtitle"]]

[[!template text="""My init file has lots of classes,""" start="00:19:19.823" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and by the way, instead of""" start="00:19:22.186" video="mainVideo-repl" id="subtitle"]]
[[!template text="""keeping many small files with many things,""" start="00:19:24.702" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I put lots of stuff in just one big init file.""" start="00:19:28.637" video="mainVideo-repl" id="subtitle"]]
[[!template text="""My init file has lots of classes,""" start="00:19:33.000" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and lots of global functions and lots of cruft,""" start="00:19:35.521" video="mainVideo-repl" id="subtitle"]]
[[!template text="""so people hate that, of course.""" start="00:19:39.188" video="mainVideo-repl" id="subtitle"]]
[[!template text="""This is an example.""" start="00:19:43.700" video="mainVideo-repl" id="subtitle"]]
[[!template text="""This is the index at the top of my init file.""" start="00:19:46.341" video="mainVideo-repl" id="subtitle"]]
[[!template text="""The classes start here. Then we have some functions""" start="00:19:52.416" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and then we have functions that load certain packages,""" start="00:19:57.542" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and then we have cruft, whatever.""" start="00:20:02.480" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Most people think that my style of using Lua""" start="00:20:06.580" video="mainVideo-repl" id="subtitle"]]
[[!template text="""is dirty and dangerous,""" start="00:20:08.924" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and they wouldn't touch my Lua code with a 10 feet pole,""" start="00:20:10.123" video="mainVideo-repl" id="subtitle"]]
[[!template text="""but most of the things""" start="00:20:14.288" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that I'm going to present here in this presentation""" start="00:20:15.969" video="mainVideo-repl" id="subtitle"]]
[[!template text="""are ideas that should be easy to port to other environments""" start="00:20:19.257" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and other languages, especially the diagrams,""" start="00:20:23.051" video="mainVideo-repl" id="subtitle"]]
[[!template text="""so the code is not so important.""" start="00:20:27.739" video="mainVideo-repl" id="subtitle"]]

[[!template new="1" text="""LaTeX and LuaLaTeX""" start="00:20:31.000" video="mainVideo-repl" id="subtitle"]]

[[!template text="""Now let me talk a bit about LaTeX, LuaLaTeX,""" start="00:20:31.000" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that is LaTeX with the Lua interpreter embedded inside""" start="00:20:34.641" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and two ways of generating pictures in LaTeX:""" start="00:20:39.250" video="mainVideo-repl" id="subtitle"]]
[[!template text="""TikZ that is very famous,""" start="00:20:43.183" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and Pict2e that is not very famous""" start="00:20:45.116" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and that is very low level,""" start="00:20:48.312" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and I think that not many people use.""" start="00:20:50.645" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I said before that when I learned Lua,""" start="00:20:53.840" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I realized that it was very good""" start="00:20:57.049" video="mainVideo-repl" id="subtitle"]]
[[!template text="""for writing literal languages.""" start="00:21:00.355" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I was doing my PhD at the time""" start="00:21:03.360" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and typesetting the diagrams for my PhD thesis""" start="00:21:05.987" video="mainVideo-repl" id="subtitle"]]
[[!template text="""was very boring.""" start="00:21:09.970" video="mainVideo-repl" id="subtitle"]]
[[!template text="""One of the things that I did was that""" start="00:21:11.240" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I created a literal language""" start="00:21:13.865" video="mainVideo-repl" id="subtitle"]]
[[!template text="""for typesetting the diagrams for me.""" start="00:21:15.721" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It was called Dednat because initially""" start="00:21:19.340" video="mainVideo-repl" id="subtitle"]]
[[!template text="""it only generated diagrams for natural deduction""" start="00:21:22.822" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and then it had several versions.""" start="00:21:26.800" video="mainVideo-repl" id="subtitle"]]
[[!template text="""These are the slides from my presentation about Dednat6""" start="00:21:30.440" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and Dednat6 is an extensible semi preprocessor""" start="00:21:34.380" video="mainVideo-repl" id="subtitle"]]
[[!template text="""for LuaLaTeX that understands diagrams in ASCII art""" start="00:21:38.991" video="mainVideo-repl" id="subtitle"]]
[[!template text="""in the sense that when I have a TeX file that has this,""" start="00:21:43.692" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and when Dednat6 is loaded,""" start="00:21:49.035" video="mainVideo-repl" id="subtitle"]]
[[!template text="""when I get the right comments,""" start="00:21:52.144" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Dednat6 interprets this block here""" start="00:21:55.709" video="mainVideo-repl" id="subtitle"]]
[[!template text="""as something that defines this diagram.""" start="00:22:00.343" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It interprets this diagram here,""" start="00:22:05.096" video="mainVideo-repl" id="subtitle"]]
[[!template text="""this diagram in the comments here,""" start="00:22:07.829" video="mainVideo-repl" id="subtitle"]]
[[!template text="""as something that defines a diagram called `foo`,""" start="00:22:10.644" video="mainVideo-repl" id="subtitle"]]
[[!template text="""a deduction called `foo`, and it generates this code here""" start="00:22:16.433" video="mainVideo-repl" id="subtitle"]]
[[!template text="""so that we can just invoke the definition of the deduction""" start="00:22:23.065" video="mainVideo-repl" id="subtitle"]]
[[!template text="""by typing `\ded{foo}`.""" start="00:22:28.868" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Dednat6 also supports another language""" start="00:22:31.720" video="mainVideo-repl" id="subtitle"]]
[[!template text="""for typesetting bidimensional diagrams with arrows and stuff""" start="00:22:36.149" video="mainVideo-repl" id="subtitle"]]
[[!template text="""for category theory and blah blah.""" start="00:22:40.580" video="mainVideo-repl" id="subtitle"]]
[[!template text="""The specifications of these diagrams""" start="00:22:43.123" video="mainVideo-repl" id="subtitle"]]
[[!template text="""look like this. Here is a very good example.""" start="00:22:46.100" video="mainVideo-repl" id="subtitle"]]
[[!template text="""This is a huge diagram. Sorry, one second.""" start="00:22:53.866" video="mainVideo-repl" id="subtitle"]]
[[!template text="""So the source code that generates this diagram here""" start="00:23:00.940" video="mainVideo-repl" id="subtitle"]]
[[!template text="""is just this thing at the left. It's very visual.""" start="00:23:04.758" video="mainVideo-repl" id="subtitle"]]
[[!template text="""We can typeset the diagram in ASCII art here.""" start="00:23:08.629" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Then in this part here,""" start="00:23:11.843" video="mainVideo-repl" id="subtitle"]]
[[!template text="""we tell how the nodes are to be joined,""" start="00:23:14.435" video="mainVideo-repl" id="subtitle"]]
[[!template text="""which arrows have to have annotations, and so on.""" start="00:23:18.274" video="mainVideo-repl" id="subtitle"]]
[[!template text="""This language is extensible in the sense that""" start="00:23:22.880" video="mainVideo-repl" id="subtitle"]]
[[!template text="""here, comments that start""" start="00:23:30.951" video="mainVideo-repl" id="subtitle"]]
[[!template text="""with `%:` are interpreted as definitions""" start="00:23:37.280" video="mainVideo-repl" id="subtitle"]]
[[!template text="""for tree diagrams,""" start="00:23:42.691" video="mainVideo-repl" id="subtitle"]]
[[!template text="""lines that start with `%D`""" start="00:23:44.820" video="mainVideo-repl" id="subtitle"]]
[[!template text="""define 2D diagrams with arrows and stuff,""" start="00:23:49.395" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and lines that start with command `%L`""" start="00:23:53.762" video="mainVideo-repl" id="subtitle"]]
[[!template text="""contain blocks of Lua code that we can use""" start="00:23:57.684" video="mainVideo-repl" id="subtitle"]]
[[!template text="""to extend the interpreter on the flag.""" start="00:24:01.198" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Anyway, here are some recent examples""" start="00:24:05.528" video="mainVideo-repl" id="subtitle"]]
[[!template text="""of diagrams that I used Dednat6 to typeset.""" start="00:24:09.747" video="mainVideo-repl" id="subtitle"]]
[[!template text="""This diagram here was generated by this specification here,""" start="00:24:16.147" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and this diagram here with the curved arrows""" start="00:24:24.495" video="mainVideo-repl" id="subtitle"]]
[[!template text="""was generated by this specification here.""" start="00:24:30.620" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Dednat6 was very easy to extend.""" start="00:24:36.200" video="mainVideo-repl" id="subtitle"]]
[[!template text="""At some point I started to use it to generate diagrams""" start="00:24:39.175" video="mainVideo-repl" id="subtitle"]]
[[!template text="""using Pict2e, mainly for the classes""" start="00:24:43.044" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that I give at the university,""" start="00:24:46.068" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I teach mathematics in a place.""" start="00:24:49.674" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Let me show an animation. Here is a diagram""" start="00:24:53.862" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that I generated with Dednat6.""" start="00:24:58.980" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It is a flipbook animation,""" start="00:25:02.326" video="mainVideo-repl" id="subtitle"]]
[[!template text="""we type page up and page down,""" start="00:25:05.386" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and we go to the next page of the book""" start="00:25:08.254" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and to the previous page of the book.""" start="00:25:10.784" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Here is the source code that generates that.""" start="00:25:13.249" video="mainVideo-repl" id="subtitle"]]
[[!template text="""This source code is not very visual,""" start="00:25:16.925" video="mainVideo-repl" id="subtitle"]]
[[!template text="""so it's quite clumsy to edit""" start="00:25:19.701" video="mainVideo-repl" id="subtitle"]]
[[!template text="""a diagram directly in the TeX file like that.""" start="00:25:21.800" video="mainVideo-repl" id="subtitle"]]

[[!template new="1" text="""Manim""" start="00:25:28.280" video="mainVideo-repl" id="subtitle"]]

[[!template text="""These diagrams were inspired by something called Manim.""" start="00:25:28.280" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I've forgotten the name of the guy, but it's a guy""" start="00:25:33.438" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that makes many videos about mathematics,""" start="00:25:36.714" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and he created this library called Manim""" start="00:25:39.347" video="mainVideo-repl" id="subtitle"]]
[[!template text="""for generating his animations.""" start="00:25:43.374" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Other people adapted his library to make it more accessible.""" start="00:25:46.418" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I tried to learn it, but each animation,""" start="00:25:52.084" video="mainVideo-repl" id="subtitle"]]
[[!template text="""even an animation with very few frames,""" start="00:25:55.800" video="mainVideo-repl" id="subtitle"]]
[[!template text="""each animation took ages to render, so it wasn't fun.""" start="00:25:59.192" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Animations and PDFs can be rendered in seconds,""" start="00:26:03.771" video="mainVideo-repl" id="subtitle"]]
[[!template text="""so these things were fun for me""" start="00:26:08.346" video="mainVideo-repl" id="subtitle"]]
[[!template text="""because my laptop is very slow and Manim was not fun.""" start="00:26:11.161" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Anyway, writing code like this inside a TeX file""" start="00:26:17.440" video="mainVideo-repl" id="subtitle"]]
[[!template text="""was not very fun because it was hard to debug.""" start="00:26:24.264" video="mainVideo-repl" id="subtitle"]]

[[!template new="1" text="""Generating diagrams from REPLs""" start="00:26:30.880" video="mainVideo-repl" id="subtitle"]]

[[!template text="""In 2022, I started to play with ways""" start="00:26:30.880" video="mainVideo-repl" id="subtitle"]]
[[!template text="""of generating these diagrams from REPLs""" start="00:26:36.511" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and I found a way for Pict2e and a way for Tikz.""" start="00:26:42.000" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Each one of these ways became a video.""" start="00:26:46.310" video="mainVideo-repl" id="subtitle"]]
[[!template text="""If you go to the list of first class videos of eev,""" start="00:26:49.520" video="mainVideo-repl" id="subtitle"]]
[[!template text="""you're going to see""" start="00:26:53.221" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that there's a video about Pict2e here""" start="00:26:55.089" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and a video about Tikz.""" start="00:26:59.011" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Here you have some information""" start="00:27:01.159" video="mainVideo-repl" id="subtitle"]]
[[!template text="""like length and explanation, etc.""" start="00:27:04.188" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Here are the pages for these videos.""" start="00:27:07.509" video="mainVideo-repl" id="subtitle"]]
[[!template text="""My page about the video about Pict2e is like this.""" start="00:27:11.514" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It has some diagrams. This one is much nicer.""" start="00:27:15.992" video="mainVideo-repl" id="subtitle"]]
[[!template text="""A lot of people watched that video. I mean,""" start="00:27:20.800" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I thought that 250 people watched it.""" start="00:27:26.606" video="mainVideo-repl" id="subtitle"]]
[[!template text="""For me, that's a million of people.""" start="00:27:31.080" video="mainVideo-repl" id="subtitle"]]
[[!template text="""This video is about how to extract diagrams""" start="00:27:35.345" video="mainVideo-repl" id="subtitle"]]
[[!template text="""from the Tikz manual, and how to run those examples in REPL""" start="00:27:40.403" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and modify them bit by bit. This is a screenshot.""" start="00:27:46.513" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Let me go back. At that point,""" start="00:27:52.937" video="mainVideo-repl" id="subtitle"]]
[[!template text="""these things were just prototypes,""" start="00:27:57.433" video="mainVideo-repl" id="subtitle"]]
[[!template text="""the code was not very nice,""" start="00:28:01.800" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and in this year I wrote...""" start="00:28:04.804" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I was able to unify those two ways of generating PDFs,""" start="00:28:07.593" video="mainVideo-repl" id="subtitle"]]
[[!template text="""the one for Tikz and the one for Pict2e.""" start="00:28:12.124" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I unified them with many other things""" start="00:28:15.666" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that generated diagrams.""" start="00:28:19.197" video="mainVideo-repl" id="subtitle"]]
[[!template text="""The basis of these things is something called Show2.lua.""" start="00:28:21.299" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I'm not going to just show its details now,""" start="00:28:28.431" video="mainVideo-repl" id="subtitle"]]
[[!template text="""but it's an extension that generates Tikz code.""" start="00:28:33.936" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It's just this. We can specify a diagram""" start="00:28:38.776" video="mainVideo-repl" id="subtitle"]]
[[!template text="""with just a block like this, and then if we run `show00`,""" start="00:28:43.306" video="mainVideo-repl" id="subtitle"]]
[[!template text="""it returns a string""" start="00:28:50.539" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that is just the inner body of the TeX file.""" start="00:28:53.695" video="mainVideo-repl" id="subtitle"]]
[[!template text="""If we run this, we see the whole TeX file.""" start="00:28:59.480" video="mainVideo-repl" id="subtitle"]]
[[!template text="""If we run this we save the TeX file and""" start="00:29:02.307" video="mainVideo-repl" id="subtitle"]]
[[!template text="""we compile the TeX file to generate a PDF.""" start="00:29:05.200" video="mainVideo-repl" id="subtitle"]]
[[!template text="""If we run this, we show the PDF""" start="00:29:09.197" video="mainVideo-repl" id="subtitle"]]
[[!template text="""in the lower right window.""" start="00:29:12.558" video="mainVideo-repl" id="subtitle"]]
[[!template text="""That's the same thing for all my recent programs""" start="00:29:15.079" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that generate PDFs. They are all integrated.""" start="00:29:20.027" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Here is the basis for all my modules""" start="00:29:23.811" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that generate diagrams with Pict2e.""" start="00:29:28.268" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Its demos are not very interesting.""" start="00:29:31.424" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Let me show some demos of extensions""" start="00:29:34.338" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that do interesting things. This is a diagram""" start="00:29:38.557" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that I created by editing it in a REPL,""" start="00:29:43.724" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I create several Pict objects here.""" start="00:29:47.902" video="mainVideo-repl" id="subtitle"]]
[[!template text="""If I execute this, it compiles the object and""" start="00:29:51.872" video="mainVideo-repl" id="subtitle"]]
[[!template text="""generates a PDF. If I tap this, here is the PDF.""" start="00:29:57.819" video="mainVideo-repl" id="subtitle"]]
[[!template text="""If I just ask Lua to display what is pux here,""" start="00:30:04.524" video="mainVideo-repl" id="subtitle"]]
[[!template text="""it shows the source code in Pict2e of the diagram.""" start="00:30:10.920" video="mainVideo-repl" id="subtitle"]]
[[!template text="""The nice thing is that it is indented,""" start="00:30:17.436" video="mainVideo-repl" id="subtitle"]]
[[!template text="""so it's easy to debug the Pict2e code.""" start="00:30:20.933" video="mainVideo-repl" id="subtitle"]]
[[!template text="""If anyone is interested, the module that does the tricks""" start="00:30:24.349" video="mainVideo-repl" id="subtitle"]]
[[!template text="""for indentation is very easy to understand.""" start="00:30:28.505" video="mainVideo-repl" id="subtitle"]]
[[!template text="""it has lots of tests and test blocks,""" start="00:30:31.948" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and I think that its data structures are easy to understand.""" start="00:30:34.921" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Anyway, here is another example, the show is here.""" start="00:30:47.439" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It generates a 3D diagram.""" start="00:30:57.905" video="mainVideo-repl" id="subtitle"]]

[[!template new="1" text="""Parsers""" start="00:31:03.240" video="mainVideo-repl" id="subtitle"]]

[[!template text="""Now let me talk about parsers""" start="00:31:03.240" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and REPLs in a very strange place.""" start="00:31:05.898" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I mean, using REPLs to build parsers step by step""" start="00:31:08.998" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and replacing parts by more complex parts.""" start="00:31:15.149" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I said that Lua is very minimalistic,""" start="00:31:20.439" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and everybody knows that""" start="00:31:24.493" video="mainVideo-repl" id="subtitle"]]
[[!template text="""implementations of regular expressions""" start="00:31:26.965" video="mainVideo-repl" id="subtitle"]]
[[!template text="""are big and complex. So instead of coming""" start="00:31:30.720" video="mainVideo-repl" id="subtitle"]]
[[!template text="""with full regular expressions,""" start="00:31:33.974" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Lua comes with something called patterns""" start="00:31:36.376" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and a library function called string.match.""" start="00:31:41.321" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Here is a copy of the part of the manual""" start="00:31:46.628" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that explains a part of the syntax of patterns.""" start="00:31:50.821" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Here's how string.match is described in the manual.""" start="00:31:55.729" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It's just this: looks for the first match of pattern""" start="00:32:00.091" video="mainVideo-repl" id="subtitle"]]
[[!template text="""in the string s, blah blah blah.""" start="00:32:04.537" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Then we have to go to the other section of the manual""" start="00:32:06.546" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that explains patterns. Lua patterns are so simple,""" start="00:32:10.077" video="mainVideo-repl" id="subtitle"]]
[[!template text="""so limited, that they don't even have""" start="00:32:18.198" video="mainVideo-repl" id="subtitle"]]
[[!template text="""the alternation operator.""" start="00:32:23.222" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Here is how it is described in the elisp manual,""" start="00:32:26.659" video="mainVideo-repl" id="subtitle"]]
[[!template text="""`\|` specifies an alternative, blah blah blah.""" start="00:32:33.136" video="mainVideo-repl" id="subtitle"]]
[[!template text="""When we want to build more complex regular expressions,""" start="00:32:39.678" video="mainVideo-repl" id="subtitle"]]
[[!template text="""patterns, grammars, etc.,""" start="00:32:45.880" video="mainVideo-repl" id="subtitle"]]
[[!template text="""we have to use an external library for that.""" start="00:32:48.366" video="mainVideo-repl" id="subtitle"]]
[[!template text="""No, sorry, a library that is external,""" start="00:32:52.669" video="mainVideo-repl" id="subtitle"]]
[[!template text="""but that was written by one of the authors of Lua itself.""" start="00:32:56.208" video="mainVideo-repl" id="subtitle"]]
[[!template text="""This library is called Lpeg.""" start="00:33:01.472" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Its manual says Lpeg is""" start="00:33:03.944" video="mainVideo-repl" id="subtitle"]]
[[!template text="""a new pattern matching library for Lua""" start="00:33:06.331" video="mainVideo-repl" id="subtitle"]]
[[!template text="""based on parsing expression grammars (PEGs).""" start="00:33:09.654" video="mainVideo-repl" id="subtitle"]]
[[!template text="""The manual is very terse.""" start="00:33:14.773" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I found it incredibly hard to read.""" start="00:33:17.781" video="mainVideo-repl" id="subtitle"]]
[[!template text="""it doesn't have any diagrams.""" start="00:33:21.946" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It has some examples, though.""" start="00:33:25.416" video="mainVideo-repl" id="subtitle"]]
[[!template text="""The Lua wiki has a big page called Lpeg Tutorial""" start="00:33:28.770" video="mainVideo-repl" id="subtitle"]]
[[!template text="""with lots of examples, but it also doesn't have diagrams.""" start="00:33:34.017" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I found some things incredibly hard to understand.""" start="00:33:39.560" video="mainVideo-repl" id="subtitle"]]
[[!template text="""For example, this is something""" start="00:33:43.132" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that is in the manual of Lpeg that I saw,""" start="00:33:45.080" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and I thought, wow, great, this makes all sense""" start="00:33:48.062" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and this is going to be very useful.""" start="00:33:51.480" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It's a way to build grammars that can be recursive""" start="00:33:53.947" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and they sort of can encode BNF grammars,""" start="00:33:57.280" video="mainVideo-repl" id="subtitle"]]
[[!template text="""we just have to translate the BNF a bit""" start="00:34:01.301" video="mainVideo-repl" id="subtitle"]]
[[!template text="""to get rid of some recursions""" start="00:34:05.129" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and to translate them to something else.""" start="00:34:07.593" video="mainVideo-repl" id="subtitle"]]
[[!template text="""The manual also has some things that I thought,""" start="00:34:10.960" video="mainVideo-repl" id="subtitle"]]
[[!template text="""oh no, I don't have any idea of what this thing does.""" start="00:34:14.338" video="mainVideo-repl" id="subtitle"]]
[[!template text="""In fact, I saw these things for the first time""" start="00:34:17.846" video="mainVideo-repl" id="subtitle"]]
[[!template text="""more than 10 years ago, and they only started to make sense""" start="00:34:20.769" video="mainVideo-repl" id="subtitle"]]
[[!template text="""one year ago. One example is group captures.""" start="00:34:27.295" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Lpeg also comes with a module called the re module.""" start="00:34:32.273" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Let me pronounce it in Portuguese, the re module.""" start="00:34:37.835" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Its manual says the re module""" start="00:34:43.183" video="mainVideo-repl" id="subtitle"]]
[[!template text="""provided by the file re.lua in the distribution""" start="00:34:45.742" video="mainVideo-repl" id="subtitle"]]
[[!template text="""supports some odd conventional regular expression syntax""" start="00:34:49.504" video="mainVideo-repl" id="subtitle"]]
[[!template text="""for pattern usage within lpeg. This is a quick reference.""" start="00:34:56.758" video="mainVideo-repl" id="subtitle"]]
[[!template text="""This thing is very brief. It has some nice examples,""" start="00:35:04.520" video="mainVideo-repl" id="subtitle"]]
[[!template text="""but it's hard to understand anyway.""" start="00:35:08.465" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Here are some comments about""" start="00:35:11.120" video="mainVideo-repl" id="subtitle"]]
[[!template text="""my attempts to learn re.lua. This is a class.""" start="00:35:14.181" video="mainVideo-repl" id="subtitle"]]
[[!template text="""In this case, it's a very small class.""" start="00:35:18.632" video="mainVideo-repl" id="subtitle"]]
[[!template text="""This file implements a `pm` method.""" start="00:35:22.362" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I'm going to show examples of other `pm` methods very soon.""" start="00:35:26.092" video="mainVideo-repl" id="subtitle"]]
[[!template text="""So this is a `pm` method for re.lua""" start="00:35:31.401" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that lets us compare the syntax of lua patterns, lpeg,""" start="00:35:34.697" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and re. See this example here. If we run this,""" start="00:35:40.302" video="mainVideo-repl" id="subtitle"]]
[[!template text="""it loads my version of lpeg, no sorry,""" start="00:35:46.632" video="mainVideo-repl" id="subtitle"]]
[[!template text="""my version of lpegrex. It shows that""" start="00:35:51.380" video="mainVideo-repl" id="subtitle"]]
[[!template text="""when we apply the `pm` method to this Lua pattern,""" start="00:35:56.014" video="mainVideo-repl" id="subtitle"]]
[[!template text="""this lpeg pattern, and this re pattern,""" start="00:36:01.553" video="mainVideo-repl" id="subtitle"]]
[[!template text="""they all give the same results.""" start="00:36:05.960" video="mainVideo-repl" id="subtitle"]]
[[!template text="""So we can use this kind of thing here to show""" start="00:36:08.239" video="mainVideo-repl" id="subtitle"]]
[[!template text="""how to translate from Lua patterns that are familiar""" start="00:36:11.513" video="mainVideo-repl" id="subtitle"]]
[[!template text="""because they are similar to regular expressions,""" start="00:36:15.589" video="mainVideo-repl" id="subtitle"]]
[[!template text="""only weaker, to lpeg that is super weird,""" start="00:36:19.280" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and to re that is not so weird.""" start="00:36:25.252" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Anyway, the comment says that in 2012, I had a project""" start="00:36:30.085" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that needed a precedence parser""" start="00:36:35.426" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that could parse arithmetical expressions""" start="00:36:38.591" video="mainVideo-repl" id="subtitle"]]
[[!template text="""with the right precedences. At that point""" start="00:36:42.278" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I was still struggling with pure lpeg""" start="00:36:46.315" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and I couldn't do much with it,""" start="00:36:49.032" video="mainVideo-repl" id="subtitle"]]
[[!template text="""so I tried to learn re.lua instead,""" start="00:36:51.319" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and I wrote this old class here that allowed me to use""" start="00:36:54.577" video="mainVideo-repl" id="subtitle"]]
[[!template text="""a preprocessor on patterns for Lua.""" start="00:36:59.292" video="mainVideo-repl" id="subtitle"]]
[[!template text="""The thing is that with this preprocessor""" start="00:37:01.756" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I could specify precedence grammars using this thing here""" start="00:37:04.835" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that worked but was super clumsy,""" start="00:37:10.921" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and I gave up after a few attempts.""" start="00:37:14.489" video="mainVideo-repl" id="subtitle"]]
[[!template text="""And in 2022 I heard about something called lpegrex""" start="00:37:18.160" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that was a kind of extension of re,""" start="00:37:25.633" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and it was much more powerful than re.lua,""" start="00:37:30.760" video="mainVideo-repl" id="subtitle"]]
[[!template text="""but after a while I realized that""" start="00:37:33.046" video="mainVideo-repl" id="subtitle"]]
[[!template text="""it had the same defects as re.lua.""" start="00:37:35.785" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Let me explain that,""" start="00:37:38.766" video="mainVideo-repl" id="subtitle"]]
[[!template text="""because it has all to do with the things""" start="00:37:40.699" video="mainVideo-repl" id="subtitle"]]
[[!template text="""about black boxes and magic that I told in the beginning.""" start="00:37:43.920" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Neither re.lua or lpegrex had some features that I needed.""" start="00:37:52.027" video="mainVideo-repl" id="subtitle"]]
[[!template text="""They received a pattern that was specified as a string""" start="00:37:59.047" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and it converted that into an lpeg pattern,""" start="00:38:05.375" video="mainVideo-repl" id="subtitle"]]
[[!template text="""but it didn't let us explore the lpeg patterns""" start="00:38:08.869" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that it generated.""" start="00:38:12.520" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Their code was written in a way that was REPL-unfriendly.""" start="00:38:14.530" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I couldn't modify parts of the code bit by bit in a REPL""" start="00:38:20.663" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and try to change the code""" start="00:38:26.282" video="mainVideo-repl" id="subtitle"]]
[[!template text="""without changing the original file, say.""" start="00:38:28.944" video="mainVideo-repl" id="subtitle"]]
[[!template text="""The code was very hard to explore, to hack,""" start="00:38:32.036" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and to extend in my opinion.""" start="00:38:35.354" video="mainVideo-repl" id="subtitle"]]
[[!template text="""The documentation was not very clear,""" start="00:38:38.239" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and I sent wonderful messages to the""" start="00:38:42.019" video="mainVideo-repl" id="subtitle"]]
[[!template text="""developer of lpegrex, and he was too busy to help me.""" start="00:38:45.600" video="mainVideo-repl" id="subtitle"]]
[[!template text="""He answered very briefly. To be honest, I felt rejected.""" start="00:38:51.014" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I felt that I wasn't doing anything interesting, whatever.""" start="00:38:57.211" video="mainVideo-repl" id="subtitle"]]

[[!template new="1" text="""ELpeg1.lua""" start="00:39:03.200" video="mainVideo-repl" id="subtitle"]]

[[!template text="""So in 2022, I was trying to learn lpegrex""" start="00:39:03.200" video="mainVideo-repl" id="subtitle"]]
[[!template text="""because I was thinking that it would solve my problems,""" start="00:39:07.471" video="mainVideo-repl" id="subtitle"]]
[[!template text="""but it didn't. It didn't have the features that I needed,""" start="00:39:13.200" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and it was hard to extend and""" start="00:39:16.667" video="mainVideo-repl" id="subtitle"]]
[[!template text="""how to explore and hard to debug.""" start="00:39:18.400" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I decided to rewrite it in a more hacker-friendly way,""" start="00:39:22.303" video="mainVideo-repl" id="subtitle"]]
[[!template text="""in the sense that it was modular""" start="00:39:28.960" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and I could replace any part of the module from a REPL.""" start="00:39:32.036" video="mainVideo-repl" id="subtitle"]]
[[!template text="""My version of it was called ELpeg1.lua.""" start="00:39:37.160" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I decided that in my version I wouldn't""" start="00:39:42.641" video="mainVideo-repl" id="subtitle"]]
[[!template text="""have the part that receives a grammar""" start="00:39:48.120" video="mainVideo-repl" id="subtitle"]]
[[!template text="""specified as a string and converts that to lpeg.""" start="00:39:51.241" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I would just have the backend part""" start="00:39:55.266" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that are the functions in lpeg""" start="00:39:58.985" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that let us specify powerful grammars.""" start="00:40:02.172" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Let me go back. Let me explain a bit about lpeg.""" start="00:40:06.320" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Lua has coercions. The `+` expects to receive two numbers.""" start="00:40:15.162" video="mainVideo-repl" id="subtitle"]]
[[!template text="""If one of its arguments or both of them are strings,""" start="00:40:20.781" video="mainVideo-repl" id="subtitle"]]
[[!template text="""it converts the strings to numbers.""" start="00:40:25.931" video="mainVideo-repl" id="subtitle"]]
[[!template text="""So in this case here, `2 + &quot;3&quot;` returns the number 5.""" start="00:40:30.117" video="mainVideo-repl" id="subtitle"]]
[[!template text="""This is the concatenation operator.""" start="00:40:37.092" video="mainVideo-repl" id="subtitle"]]
[[!template text="""It expects to receive strings. In this case, it will""" start="00:40:40.441" video="mainVideo-repl" id="subtitle"]]
[[!template text="""convert the number 2 to the string &quot;2&quot;""" start="00:40:44.960" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and the concatenation of these two things will be""" start="00:40:47.542" video="mainVideo-repl" id="subtitle"]]
[[!template text="""&quot;23&quot;. Oops, sorry, &quot;23&quot; as a string.""" start="00:40:50.960" video="mainVideo-repl" id="subtitle"]]
[[!template text="""lpeg also has some coercions. I usually set these globals""" start="00:40:55.918" video="mainVideo-repl" id="subtitle"]]
[[!template text="""to let me write my grammars in a very compact way.""" start="00:41:04.480" video="mainVideo-repl" id="subtitle"]]
[[!template text="""So instead of lpeg.B, lpeg.C, etc.""" start="00:41:10.014" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I use globals like B, C, and so on.""" start="00:41:13.812" video="mainVideo-repl" id="subtitle"]]
[[!template text="""And with these globals I can write""" start="00:41:17.879" video="mainVideo-repl" id="subtitle"]]
[[!template text="""things like this, `C(1) * &quot;_&quot;`. And lpeg knows that lpeg.C,""" start="00:41:21.720" video="mainVideo-repl" id="subtitle"]]
[[!template text="""sorry, it sort of expands these to lpeg.C,""" start="00:41:36.048" video="mainVideo-repl" id="subtitle"]]
[[!template text="""but lpeg.C expects to receive an lpeg pattern""" start="00:41:41.148" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and 1 is not yet an lpeg pattern.""" start="00:41:43.591" video="mainVideo-repl" id="subtitle"]]
[[!template text="""So it is coerced into an lpeg pattern by calling lpeg.P.""" start="00:41:48.548" video="mainVideo-repl" id="subtitle"]]
[[!template text="""So this short thing here becomes equivalent to""" start="00:41:53.348" video="mainVideo-repl" id="subtitle"]]
[[!template text="""`lpeg.C(lpeg.P(1))`. And the multiplication when at least one of""" start="00:42:02.482" video="mainVideo-repl" id="subtitle"]]
[[!template text="""its arguments is an lpeg pattern, it expects to receive two lpeg patterns. And in this""" start="00:42:07.200" video="mainVideo-repl" id="subtitle"]]
[[!template text="""case the one at the right is just a string, so it is coerced to an lpeg pattern by using""" start="00:42:13.320" video="mainVideo-repl" id="subtitle"]]
[[!template text="""lpeg.P. With this idea we can sort of understand this comparison here. I mean, let me run it""" start="00:42:19.200" video="mainVideo-repl" id="subtitle"]]
[[!template text="""again. This first part is very similar to a regular expression here at the left. And""" start="00:42:29.360" video="mainVideo-repl" id="subtitle"]]
[[!template text="""when we apply this lpeg, sorry, this lua pattern to this subject here, the result is this thing""" start="00:42:37.440" video="mainVideo-repl" id="subtitle"]]
[[!template text="""here, this thing, this thing and this thing. I'm going to call each one of these results""" start="00:42:51.440" video="mainVideo-repl" id="subtitle"]]
[[!template text="""captures. So each of these things between parentheses captures a substring of the original""" start="00:42:56.040" video="mainVideo-repl" id="subtitle"]]
[[!template text="""string and these captured substrings are returned in a certain order. Here is how to express""" start="00:43:04.080" video="mainVideo-repl" id="subtitle"]]
[[!template text="""the same thing in lpeg. It's very cryptic, but it's a good way to understand some basic""" start="00:43:11.520" video="mainVideo-repl" id="subtitle"]]
[[!template text="""operators of lpeg. I mean, we can look at the menu and understand what C, S and R do""" start="00:43:20.720" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and also exponentiation. And this strange thing here receives this string here, runs""" start="00:43:29.880" video="mainVideo-repl" id="subtitle"]]
[[!template text="""a function that I have defined that converts it to an object of a certain class and that""" start="00:43:41.360" video="mainVideo-repl" id="subtitle"]]
[[!template text="""class represents re patterns. So this thing is treated as a pattern for re.lua and it""" start="00:43:46.760" video="mainVideo-repl" id="subtitle"]]
[[!template text="""is matched again the string and it returns the same thing as the other one. Also this""" start="00:43:55.240" video="mainVideo-repl" id="subtitle"]]
[[!template text="""thing here also has a comparison with lpeg.rex, but these patterns are very, very trivial.""" start="00:44:04.040" video="mainVideo-repl" id="subtitle"]]
[[!template text="""They don't do anything very strange. So let's go back and see what kinds of very strange""" start="00:44:10.680" video="mainVideo-repl" id="subtitle"]]
[[!template text="""things there are. Here is the page of lpeg.rex at GitHub. Here is the documentation. It's""" start="00:44:17.340" video="mainVideo-repl" id="subtitle"]]
[[!template text="""relatively brief. It explains lpeg.rex as being an extension of re.lua. So""" start="00:44:31.480" video="mainVideo-repl" id="subtitle"]]
[[!template text="""it explains mainly the additional features. Here is a quick reference that explains only""" start="00:44:39.120" video="mainVideo-repl" id="subtitle"]]
[[!template text="""the additional features. Some of these things I was able to understand by struggling a lot,""" start="00:44:44.880" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and some I wasn't able to even by spending several evenings trying to build examples.""" start="00:44:56.840" video="mainVideo-repl" id="subtitle"]]
[[!template text="""This is something very nice. lpeg.rex comes with some example parsers. Here is""" start="00:45:08.720" video="mainVideo-repl" id="subtitle"]]
[[!template text="""a parser that parses the lua grammar. I mean, this is the grammar for lua 5.4 at the end""" start="00:45:16.600" video="mainVideo-repl" id="subtitle"]]
[[!template text="""of the reference manual. It's just this. And this is a kind of BNF, and this is the BNF""" start="00:45:25.720" video="mainVideo-repl" id="subtitle"]]
[[!template text="""translated to the language of lpeg.rex. This thing uses many constructions that are""" start="00:45:35.080" video="mainVideo-repl" id="subtitle"]]
[[!template text="""in re.lua and some extra constructions that are described here. With these examples,""" start="00:45:43.840" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I was able to understand some of these things here that are described here in the quick""" start="00:45:51.840" video="mainVideo-repl" id="subtitle"]]
[[!template text="""reference, but not all. So I wasn't able to use lpeg.rex by itself because some things""" start="00:46:00.280" video="mainVideo-repl" id="subtitle"]]
[[!template text="""didn't make much sense. I decided to re implement it in my own style because that""" start="00:46:13.840" video="mainVideo-repl" id="subtitle"]]
[[!template text="""would be a way to map... at the very least, map what I understood and what I didn't and""" start="00:46:21.560" video="mainVideo-repl" id="subtitle"]]
[[!template text="""learn one feature at a time, do comparisons and so on. Here I pointed to two features""" start="00:46:29.120" video="mainVideo-repl" id="subtitle"]]
[[!template text="""of lpeg. One I said, oh great, this thing can be used to define grammars, even recursive""" start="00:46:38.160" video="mainVideo-repl" id="subtitle"]]
[[!template text="""grammars and so on. And this is an &quot;oh no&quot; feature. One thing that didn't make any sense at all:""" start="00:46:44.880" video="mainVideo-repl" id="subtitle"]]
[[!template text="""group captures. One thing that I did to understand group captures was to represent them as diagrams.""" start="00:46:52.260" video="mainVideo-repl" id="subtitle"]]
[[!template text="""Of course in the beginning I was drawing these diagrams by hand, but then I realized that""" start="00:47:01.760" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I could use the bits of lpeg that I already knew to build a grammar that would parse a""" start="00:47:08.200" video="mainVideo-repl" id="subtitle"]]
[[!template text="""little language and generate these diagrams in LaTeX. I was able to make this. In""" start="00:47:16.680" video="mainVideo-repl" id="subtitle"]]
[[!template text="""this diagram here, this thing above the arrow is a piece of Lua code that specifies an lpeg""" start="00:47:24.400" video="mainVideo-repl" id="subtitle"]]
[[!template text="""pattern. This thing here at the top is the string that is being matched and the things""" start="00:47:35.520" video="mainVideo-repl" id="subtitle"]]
[[!template text="""below the under braces are the captures that each thing captures. For example, this under""" start="00:47:43.160" video="mainVideo-repl" id="subtitle"]]
[[!template text="""brace here corresponds to this pattern here that parses a single character but doesn't""" start="00:47:57.880" video="mainVideo-repl" id="subtitle"]]
[[!template text="""return any captures. This thing here parses a single B and doesn't return any captures.""" start="00:48:03.520" video="mainVideo-repl" id="subtitle"]]
[[!template text="""This thing here parses a single character and captures it. And this thing here parses""" start="00:48:10.680" video="mainVideo-repl" id="subtitle"]]
[[!template text="""the character D and captures it. And this other thing here that transforms this pattern""" start="00:48:17.800" video="mainVideo-repl" id="subtitle"]]
[[!template text="""into another pattern returns first a capture with all the string that was parsed by this""" start="00:48:24.920" video="mainVideo-repl" id="subtitle"]]
[[!template text="""pattern here and then all the captures returned by this thing here before the column. So this""" start="00:48:35.040" video="mainVideo-repl" id="subtitle"]]
[[!template text="""was a way to build concrete examples for things that the lpeg manual was explaining in a very""" start="00:48:44.000" video="mainVideo-repl" id="subtitle"]]
[[!template text="""terse way and it worked for me. Some things that were very mysterious started to make""" start="00:48:51.840" video="mainVideo-repl" id="subtitle"]]
[[!template text="""sense and I started to have intelligent questions to ask in the mailing list. With that""" start="00:48:58.600" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I was able to understand what are group captures that receive a name. Well, let me explain""" start="00:49:10.200" video="mainVideo-repl" id="subtitle"]]
[[!template text="""what this does. This thing here parses the empty string and returns this as a constant.""" start="00:49:22.040" video="mainVideo-repl" id="subtitle"]]
[[!template text="""So this is something that doesn't exist in regular expressions. It parses nothing and""" start="00:49:30.400" video="mainVideo-repl" id="subtitle"]]
[[!template text="""returns this as a capture. Then this thing here returns two constants here and parses""" start="00:49:38.520" video="mainVideo-repl" id="subtitle"]]
[[!template text="""the empty string. And this thing here, D, converts the results of this thing here into""" start="00:49:46.800" video="mainVideo-repl" id="subtitle"]]
[[!template text="""a group capture and stores it in the label D. And then here's another constant capture.""" start="00:49:54.440" video="mainVideo-repl" id="subtitle"]]

[[!template new="1" text="""Building lists""" start="00:50:04.160" video="mainVideo-repl" id="subtitle"]]

[[!template text="""I realized that these things here were similar to how Lua specifies building lists.""" start="00:50:04.160" video="mainVideo-repl" id="subtitle"]]
[[!template text="""When we build a table and we say that the first element of the table is here, this element""" start="00:50:15.560" video="mainVideo-repl" id="subtitle"]]
[[!template text="""is put at the end of the table. After that we say D equals to say 42. We are putting""" start="00:50:22.320" video="mainVideo-repl" id="subtitle"]]
[[!template text="""the 42 in the slot whose key is D. This was happening with lpeg captures but there was""" start="00:50:30.600" video="mainVideo-repl" id="subtitle"]]
[[!template text="""something very strange. These group captures could hold more than one capture, more than""" start="00:50:39.880" video="mainVideo-repl" id="subtitle"]]
[[!template text="""one value. So there was something between lists and tables. I started to use this notation""" start="00:50:49.320" video="mainVideo-repl" id="subtitle"]]
[[!template text="""to explain in my notation what they were doing. Many things started to make sense, many mysterious""" start="00:50:57.400" video="mainVideo-repl" id="subtitle"]]
[[!template text="""sentences in the manual started to make sense but some didn't. But at least I was able to""" start="00:51:09.840" video="mainVideo-repl" id="subtitle"]]
[[!template text="""send some intelligent questions to the mailing list and the author of Lua and LPEG answered""" start="00:51:20.480" video="mainVideo-repl" id="subtitle"]]
[[!template text="""some of them. He was not very happy about my questions. He told me that those diagrams""" start="00:51:26.960" video="mainVideo-repl" id="subtitle"]]
[[!template text="""were a waste of time, the manual was perfectly clear and so on, whatever. So it was weird,""" start="00:51:35.920" video="mainVideo-repl" id="subtitle"]]
[[!template text="""but I was able to understand lots of things from his answers. So this is a copy of one""" start="00:51:47.280" video="mainVideo-repl" id="subtitle"]]
[[!template text="""of my messages, then there's another one, another one, some of the diagrams. Then he""" start="00:51:56.440" video="mainVideo-repl" id="subtitle"]]
[[!template text="""complained about these diagrams, he said that these things here that look like table constructions""" start="00:52:02.040" video="mainVideo-repl" id="subtitle"]]
[[!template text="""do not exist, whatever. Anyway, once I understood group captures, many features were very easy""" start="00:52:10.080" video="mainVideo-repl" id="subtitle"]]
[[!template text="""to understand and I started to be able to use lpeg to build some very interesting things.""" start="00:52:22.720" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I was able to reproduce some of the features that I saw in lpegrex. Remember that this""" start="00:52:30.800" video="mainVideo-repl" id="subtitle"]]
[[!template text="""is a syntax of Lua. Here I was able to understand how these things here were translated to lpeg""" start="00:52:39.600" video="mainVideo-repl" id="subtitle"]]
[[!template text="""code, to lpeg patterns by using group captures in a certain way. I was able to implement""" start="00:52:53.400" video="mainVideo-repl" id="subtitle"]]
[[!template text="""them in ELpeg1.lua. after some time I was able to use ELpeg1.lua to build grammars that""" start="00:53:02.880" video="mainVideo-repl" id="subtitle"]]
[[!template text="""were able to parse arithmetical expressions with the right precedence. here's an example""" start="00:53:13.080" video="mainVideo-repl" id="subtitle"]]
[[!template text="""in which I built the grammar step by step and I test the current grammar and I replace""" start="00:53:21.080" video="mainVideo-repl" id="subtitle"]]
[[!template text="""a bit and then I test the new grammar and so on. You can see that the result is""" start="00:53:26.920" video="mainVideo-repl" id="subtitle"]]
[[!template text="""always a tree that is drawn in a nice two dimensional way. At this point, these powers""" start="00:53:34.400" video="mainVideo-repl" id="subtitle"]]
[[!template text="""here are returned as a list, as an operation power with several arguments here and then""" start="00:53:48.720" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I apply a kind of parsing combinator here that transforms these trees into other trees""" start="00:53:57.760" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and with these combinators here I can specify that the power is associative in a certain""" start="00:54:05.560" video="mainVideo-repl" id="subtitle"]]
[[!template text="""direction, the division is associative in another direction, the minus uses the same""" start="00:54:14.200" video="mainVideo-repl" id="subtitle"]]
[[!template text="""direction as a division and so on and they have the right precedences. So here are the""" start="00:54:22.320" video="mainVideo-repl" id="subtitle"]]
[[!template text="""tests. So here's my file ELpeg.lua, it has several classes. Each class has tests after""" start="00:54:29.520" video="mainVideo-repl" id="subtitle"]]
[[!template text="""it. I was able to implement something that lpeg.rex has that's called keywords, that's""" start="00:54:42.360" video="mainVideo-repl" id="subtitle"]]
[[!template text="""very useful for parsing problems in programming languages. I was able to implement something""" start="00:54:52.040" video="mainVideo-repl" id="subtitle"]]
[[!template text="""similar to the debugger, to the pack debugger that lpeg uses, but I was frustrated by some""" start="00:54:59.160" video="mainVideo-repl" id="subtitle"]]
[[!template text="""limitations of the debugger and I implemented my own that is much better and let me show""" start="00:55:10.640" video="mainVideo-repl" id="subtitle"]]
[[!template text="""something else. I was able to translate a good part of the Lua parser here to lpeg1.lua.""" start="00:55:23.280" video="mainVideo-repl" id="subtitle"]]
[[!template text="""I haven't finished yet but I have most of the translation here and after having all""" start="00:55:33.800" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that I was able to build other grammars very quickly. Writing new parsers finally became""" start="00:55:45.880" video="mainVideo-repl" id="subtitle"]]
[[!template text="""fun and here's one example that I showed in the beginning. If I remember correctly, I""" start="00:55:54.960" video="mainVideo-repl" id="subtitle"]]
[[!template text="""took a figure from the Wikipedia, I don't have its link now, but I specify a grammar""" start="00:56:08.560" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that parses exactly the example that appears in the Wikipedia. So with my grammar, considering""" start="00:56:15.680" video="mainVideo-repl" id="subtitle"]]
[[!template text="""that the top level entry is statement, when I parse this string here, the result is this""" start="00:56:24.280" video="mainVideo-repl" id="subtitle"]]
[[!template text="""tree and I can do some operations on that. I can define how this thing is to be converted""" start="00:56:36.680" video="mainVideo-repl" id="subtitle"]]
[[!template text="""into LaTeX. I can define other operations that convert trees into other trees and here's""" start="00:56:44.840" video="mainVideo-repl" id="subtitle"]]
[[!template text="""some tests of these operations. This is what I showed in the beginning. I'm not going to""" start="00:56:53.400" video="mainVideo-repl" id="subtitle"]]
[[!template text="""explain all the details of this thing now. This show converts this thing into LaTeX in""" start="00:57:01.760" video="mainVideo-repl" id="subtitle"]]
[[!template text="""the way specified by these instructions here. And here's the result, the LaTeX result.""" start="00:57:10.480" video="mainVideo-repl" id="subtitle"]]
[[!template text="""These diagrams here are generated by this file here that defines a simple grammar that""" start="00:57:39.320" video="mainVideo-repl" id="subtitle"]]
[[!template text="""parses this thing here and then LaTeX it in a certain way and also tests to check if this""" start="00:57:46.880" video="mainVideo-repl" id="subtitle"]]
[[!template text="""code here that is Lua code that generates an lpeg grammar, parses this subject here, and""" start="00:57:56.720" video="mainVideo-repl" id="subtitle"]]
[[!template text="""returns the expected result. So this is the code that I wanted to show. I wanted to show""" start="00:58:06.600" video="mainVideo-repl" id="subtitle"]]
[[!template text="""many more things, but I wasn't able to prepare them before the conference. And I hope that""" start="00:58:16.880" video="mainVideo-repl" id="subtitle"]]
[[!template text="""soon, for some value of soon, I'll be able to create REPL based tutorials for LPG, G and""" start="00:58:23.920" video="mainVideo-repl" id="subtitle"]]
[[!template text="""ELpeg1.Lua where Lpeg is something very famous. Here is a module of LPG. I could also do something""" start="00:58:33.240" video="mainVideo-repl" id="subtitle"]]
[[!template text="""like this for ELpeg, and ELpeg1.lua is the thing that I wrote, the one that has tests in comments""" start="00:58:42.080" video="mainVideo-repl" id="subtitle"]]
[[!template text="""and the tests usually generate trees and sometimes they generate tag code. So that's it, I wanted""" start="00:58:55.600" video="mainVideo-repl" id="subtitle"]]
[[!template text="""to present much more, but I wasn't able to prepare it. So sorry, thanks, bye!""" start="00:59:04.920" video="mainVideo-repl" id="subtitle"]]

Questions or comments? Please e-mail [eduardoochs@gmail.com](mailto:eduardoochs@gmail.com?subject=Comment%20for%20EmacsConf%202023%20repl%3A%20REPLs%20in%20strange%20places%3A%20Lua%2C%20LaTeX%2C%20LPeg%2C%20LPegRex%2C%20TikZ)


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