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

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


Introduction

[[!template new="1" text="""Hi, I'm Austin Theriault,""" start="00:00:00.000" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and this is writing a language server in OCaml""" start="00:00:01.840" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""for Emacs, fun, and profit.""" start="00:00:04.160" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Real quick, who am I?""" start="00:00:07.640" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Well, I'm a software engineer at Semgrep.""" start="00:00:08.920" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""I work on our editor integrations,""" start="00:00:10.920" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and I love working on programming languages, editors,""" start="00:00:13.240" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and cryptography.""" start="00:00:15.360" video="mainVideo-lspocaml" id="subtitle"]]

What is Semgrep?

[[!template new="1" text="""What is Semgrep?""" start="00:00:16.540" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""We're a small cybersecurity startup""" start="00:00:17.800" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""whose core product is a SaaS tool,""" start="00:00:20.040" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""which is static application security testing.""" start="00:00:21.920" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""You can think of it as like a security linter.""" start="00:00:24.760" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Normal linters will say, hey,""" start="00:00:27.800" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""you wrote ugly code, fix it.""" start="00:00:30.120" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""We'll say, hey, you wrote a SQL injection, fix that.""" start="00:00:31.920" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""We support 30+ languages,""" start="00:00:35.080" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and we have lots of customers all using different IDEs.""" start="00:00:36.960" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Why does that matter?""" start="00:00:39.320" video="mainVideo-lspocaml" id="subtitle"]]

How do we show security bugs early?

[[!template new="1" text="""Well, our goal is to show security bugs""" start="00:00:40.720" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""as early as possible in the development cycle.""" start="00:00:42.780" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""In the industry, we call this shifting left.""" start="00:00:45.240" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""And so how far left can we shift? The editor.""" start="00:00:48.480" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""So that's why it matters""" start="00:00:52.960" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""that our customers have different editors.""" start="00:00:53.620" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Our goal is to have Semgrep and the editor""" start="00:00:56.080" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""show up like other language tooling.""" start="00:00:58.920" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""And what I mean by that is I wrote some bad OCaml up here,""" start="00:01:01.320" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and the editor gave me that red squiggly and said,""" start="00:01:05.200" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""fix your OCaml, and we want Semgrep to do something similar.""" start="00:01:07.600" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""And so our goal then is to provide a similar experience""" start="00:01:12.200" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""to normal language checking.""" start="00:01:15.520" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""And then since we're a small startup,""" start="00:01:16.920" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and there's a ton of different IDEs that our customers use,""" start="00:01:19.000" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""ideally, we don't want to have to rewrite a plugin""" start="00:01:22.080" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""for every single type of editor out there.""" start="00:01:24.920" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Our other goal is abstract away""" start="00:01:27.560" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""editing and language features for editors to one code base.""" start="00:01:29.160" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Ideally, we write it once""" start="00:01:32.120" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and then plug it into all of them.""" start="00:01:33.880" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""So how can we do that, though?""" start="00:01:35.800" video="mainVideo-lspocaml" id="subtitle"]]

What is the Language Server Protocol?

[[!template new="1" text="""Well, in the process of working on this stuff,""" start="00:01:37.880" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""I found out about""" start="00:01:40.680" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""the Language Server Protocol.""" start="00:01:43.000" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""And what's great about the Language Server Protocol is""" start="00:01:44.880" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""it's a specification that defines all the ways""" start="00:01:47.280" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""that these language tools might interact""" start="00:01:50.320" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""with a development tool. And by development tool,""" start="00:01:52.680" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""I mean like VS Code, Sublime, Emacs, any of those.""" start="00:01:56.880" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""And by language tool, I mean something like PyRight, MyPy.""" start="00:02:01.600" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""So what's cool about LSP is that""" start="00:02:07.280" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""you can separate out those tools into language servers""" start="00:02:09.320" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and the development tools into language clients.""" start="00:02:13.000" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""And because they share this common specification,""" start="00:02:15.520" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""they can now interact without knowing each other.""" start="00:02:18.080" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""So it's this great abstraction that means""" start="00:02:20.360" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""all you have to do is go write one language server""" start="00:02:22.800" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and you can hook it up to a bunch of language clients""" start="00:02:25.440" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and it'll just work.""" start="00:02:27.440" video="mainVideo-lspocaml" id="subtitle"]]

Case study: Rust Analyzer

[[!template new="1" text="""So let's do a quick case study on language servers in LSP,""" start="00:02:29.040" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""just so you get an idea of why this is super cool.""" start="00:02:34.040" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""So there's this language server called Rust Analyzer.""" start="00:02:37.240" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""It's a language server for the Rust language.""" start="00:02:40.440" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""If you've ever developed in Rust,""" start="00:02:42.880" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""you'll know that takes a really long time to compile,""" start="00:02:44.120" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""but the compiler gives you fantastic feedback.""" start="00:02:46.960" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Rust has a lot of advanced language features,""" start="00:02:50.360" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""so that feedback is super important for developing.""" start="00:02:52.360" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""And so Rust Analyzer will give you that feedback instantly.""" start="00:02:55.440" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Here's a ton of things that it gives you.""" start="00:02:58.920" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Code completion, fixes, compiler errors, warnings,""" start="00:03:01.120" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""type signatures. Rust has a pretty strong type system.""" start="00:03:05.080" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""It also has this thing called lifetimes.""" start="00:03:08.680" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""A bunch of advanced language features in Rust Analyzer""" start="00:03:12.200" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""helps you manage all that""" start="00:03:15.080" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and gives you all that info""" start="00:03:16.200" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""without having to wait for it to compile.""" start="00:03:17.440" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Developing with the Rust Analyzer""" start="00:03:19.220" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""is just orders of magnitude easier""" start="00:03:21.520" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""than just trying to write Rust straight.""" start="00:03:24.320" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Rust Analyzer, fantastic. They went and they developed it,""" start="00:03:26.520" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and now you can go use that in Emacs, NeoVim,""" start="00:03:30.920" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""VS Code, wherever.""" start="00:03:33.640" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""So you can develop Rust in a way that's relatively efficient""" start="00:03:35.240" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""without having to give up your favorite editor.""" start="00:03:39.080" video="mainVideo-lspocaml" id="subtitle"]]

Rust Analyzer in action

[[!template new="1" text="""So here's a quick little demo""" start="00:03:42.760" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""of all the cool things it can do.""" start="00:03:44.400" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""So you can see I typed an error.""" start="00:03:46.320" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""It tells me that I wrote an error.""" start="00:03:48.120" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""I used the incorrect lifetime,""" start="00:03:50.720" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""which is some advanced language feature,""" start="00:03:52.520" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and it'll let me know that.""" start="00:03:54.160" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""I expanded a Rust macro just there,""" start="00:03:55.160" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""which is similar to Lisp macros,""" start="00:03:57.520" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and then I ran a single unit test,""" start="00:03:59.240" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and that's really cool because I ran a single unit test""" start="00:04:01.360" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""from my editor.""" start="00:04:04.640" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""I didn't have to go and type any commands or anything.""" start="00:04:05.440" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""It just worked.""" start="00:04:07.840" video="mainVideo-lspocaml" id="subtitle"]]

Why is this useful?

[[!template new="1" text="""So why is this just useful in general for a user?""" start="00:04:09.960" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Well, you get the same experience across editors.""" start="00:04:13.400" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Like I was saying, you don't have to give up""" start="00:04:15.800" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""one editor for another""" start="00:04:17.120" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""so you get some sort of cool language feature.""" start="00:04:18.360" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""You can easily set up and use language servers""" start="00:04:21.720" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""made for other editors""" start="00:04:23.560" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""if developers don't support your editor of choice.""" start="00:04:24.600" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Performance is not dependent on the editor.""" start="00:04:27.860" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""That's fantastic because to do all that Rust stuff,""" start="00:04:31.240" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""it takes a lot of CPU power,""" start="00:04:35.440" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and so that's going to be slow""" start="00:04:37.440" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""if your editor language is not great, not fast.""" start="00:04:40.500" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""And then bug fixes, updates, all that,""" start="00:04:43.680" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""it all comes out at the same time.""" start="00:04:47.800" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""And then from the developer perspective, well,""" start="00:04:50.120" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""adding new editors is quick and easy.""" start="00:04:53.400" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""For reference, when I wrote the Semgrep language server,""" start="00:04:55.360" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""it took me maybe two or three weeks,""" start="00:04:58.700" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""but then actually going and setting it up for VS Code,""" start="00:05:00.520" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""that took an hour. For Emacs, 30 minutes.""" start="00:05:04.000" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""IntelliJ, maybe another hour.""" start="00:05:06.440" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""So it took me a day to add support""" start="00:05:08.360" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""for three different editors,""" start="00:05:10.400" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""which was I think something like 75% of the market share""" start="00:05:11.880" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""or something crazy like that.""" start="00:05:14.800" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""So very quick. You only need one mental model.""" start="00:05:16.320" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""You don't have to figure out""" start="00:05:20.180" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""all these different extension mental models,""" start="00:05:21.080" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""how those editors work, anything like that.""" start="00:05:23.960" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""And another thing that's cool is""" start="00:05:26.520" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""you only have to write tests for the language server,""" start="00:05:28.640" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""not necessarily for the editor.""" start="00:05:30.400" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""It's great to have just one set of tests""" start="00:05:31.960" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""that you have to pass.""" start="00:05:33.840" video="mainVideo-lspocaml" id="subtitle"]]

So what about Emacs?

[[!template new="1" text="""So why does a language server protocol matter with Emacs?""" start="00:05:36.220" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Well, like I was saying before,""" start="00:05:40.160" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Emacs gets the benefit from work put into other editors.""" start="00:05:42.380" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""So we get all this language support,""" start="00:05:45.480" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and no one actually has to go and write the list for it""" start="00:05:47.760" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""or write those tools specific to Emacs.""" start="00:05:51.120" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""You get the language tooling,""" start="00:05:53.200" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""the CPU-intensive part of the editors.""" start="00:05:54.920" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""It can be written in something else.""" start="00:05:56.760" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Lisp is fast. It's not that fast.""" start="00:05:58.560" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Having that speed is fantastic. It's all asynchronous.""" start="00:06:01.320" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""It won't slow down Emacs.""" start="00:06:04.720" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""And then there's this package called `lsp-mode`,""" start="00:06:06.440" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""which is an LSP client commonly included""" start="00:06:08.920" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""in popular Emacs distributions.""" start="00:06:11.360" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""So a lot of people already have that.""" start="00:06:13.320" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""If you're using Emacs 29 or greater, you have `eglot-mode`,""" start="00:06:15.160" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""which is a lighter weight version of `lsp-mode`.""" start="00:06:18.680" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""It's just another LSP client.""" start="00:06:21.680" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""When I wrote the Semgrep language server,""" start="00:06:24.240" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Emacs 29 hadn't come out yet.""" start="00:06:26.360" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""I'm not going to talk too much about `eglot-mode`""" start="00:06:28.320" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""because I did everything in `lsp-mode`,""" start="00:06:31.480" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""but I would imagine a lot of this stuff is very similar.""" start="00:06:33.300" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Here's a list of some supported languages.""" start="00:06:37.780" video="mainVideo-lspocaml" id="subtitle"]]

Technical part - Brief communication overview

[[!template new="1" text="""Now let's get into the technical part.""" start="00:06:40.700" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""How does LSP actually work?""" start="00:06:42.640" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""So let's go over how it communicates first.""" start="00:06:45.040" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""It uses JSONRPC,""" start="00:06:47.160" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""which is just kind of like HTTP,""" start="00:06:49.760" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""but instead of sending plain text, you're sending JSON.""" start="00:06:51.960" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""So it's just sending JSON back and forth.""" start="00:06:54.620" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""It's great because it's a way""" start="00:06:56.440" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""for two programs to communicate""" start="00:06:58.540" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""without sharing a common programming language.""" start="00:06:59.960" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Transport platform agnostic,""" start="00:07:02.840" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""so it could be stdin, stdout,""" start="00:07:04.960" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""sockets, whatever. It's just JSON.""" start="00:07:07.080" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""You can send it over whatever.""" start="00:07:09.400" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""There's two different types of messages,""" start="00:07:11.140" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""a request, which requires a response from the other party,""" start="00:07:12.720" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and a notification, which does not expect a response.""" start="00:07:15.840" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""So just a quick little example,""" start="00:07:19.260" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""a user might open a document,""" start="00:07:21.760" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and then it'll send like a text document did open""" start="00:07:23.760" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and what document it was to the language server,""" start="00:07:28.080" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and then they'll change it.""" start="00:07:30.200" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Maybe they edit some code and introduce a syntax error.""" start="00:07:31.080" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""The changes will be sent to the language server,""" start="00:07:35.080" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and then the language server will publish diagnostics,""" start="00:07:37.160" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""which is those red squigglies""" start="00:07:39.220" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""I was talking about earlier,""" start="00:07:41.200" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and say, hey, syntax error or whatever here,""" start="00:07:42.560" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""or maybe the user says,""" start="00:07:45.460" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""I want to go to the definition of this function,""" start="00:07:46.920" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and then the language server will spit back,""" start="00:07:49.160" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""hey, this is where that function lives.""" start="00:07:51.240" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""All very useful,""" start="00:07:53.800" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and the communication is relatively simple,""" start="00:07:55.400" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""which is great.""" start="00:07:57.720" video="mainVideo-lspocaml" id="subtitle"]]

Example request

[[!template new="1" text="""This is what it looks like, what a request looks like.""" start="00:07:58.760" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Notifications look somewhat similar.""" start="00:08:01.240" video="mainVideo-lspocaml" id="subtitle"]]

LSP capabilities

[[!template new="1" text="""So now we know how LSP communication works,""" start="00:08:03.380" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""but how does the actual protocol work?""" start="00:08:05.880" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Well, almost all of the protocol is opt-in,""" start="00:08:09.860" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""meaning you don't have to support the entire specification,""" start="00:08:12.400" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""you can just pick and choose.""" start="00:08:15.840" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Servers and clients will then communicate""" start="00:08:17.400" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""what part of the protocol they both support,""" start="00:08:19.840" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""so they'll both say, hey,""" start="00:08:21.680" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""we support being notified when a user opens a document,""" start="00:08:22.680" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""or if they're looking for documentation.""" start="00:08:26.360" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""And so then once they agree upon what they'll both support,""" start="00:08:28.880" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""then they'll send that stuff,""" start="00:08:33.800" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""those notifications and requests back and forth.""" start="00:08:35.200" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Things like opening and closing files, diagnostics,""" start="00:08:38.580" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""code completion, hovering over stuff, type signatures,""" start="00:08:41.320" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""all of that. And what's cool is""" start="00:08:46.040" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""even though the specification is huge""" start="00:08:48.560" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and probably has everything you need,""" start="00:08:50.240" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""you can go ahead and add custom capabilities""" start="00:08:52.040" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""if you really want to.""" start="00:08:54.480" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""So you can just define a custom method,""" start="00:08:55.520" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and then now that works for you,""" start="00:08:57.980" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and now you can have that in all your editors.""" start="00:09:01.360" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""For example, Rust Analyzer""" start="00:09:03.520" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""has structural search and replace,""" start="00:09:04.560" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""which is like find and replace,""" start="00:09:06.200" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""but with respect to the structure of the code.""" start="00:09:08.160" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""And if you choose to go down this route""" start="00:09:11.600" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""with the custom capabilities,""" start="00:09:13.640" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""you do have to remember you're going to have to""" start="00:09:15.160" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""implement it in every client.""" start="00:09:16.660" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""And that's a little bit more work,""" start="00:09:18.700" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""but it's better than where we were without LSP.""" start="00:09:20.400" video="mainVideo-lspocaml" id="subtitle"]]

Tips on writing a LS

[[!template new="1" text="""So some quick tips on writing a language server.""" start="00:09:23.380" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""I'm not going to get too into this""" start="00:09:25.440" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""because it's very application-specific.""" start="00:09:27.480" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""I wrote Semgrep's in OCaml""" start="00:09:30.800" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""since our code base was almost all OCaml already,""" start="00:09:32.760" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and I wanted to leverage that.""" start="00:09:35.120" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Would not recommend""" start="00:09:36.600" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""unless you also have a code base all in OCaml.""" start="00:09:38.040" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Structure is similar to a Rust server,""" start="00:09:41.560" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""so a bunch of independent endpoints.""" start="00:09:43.640" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""I would do everything functionally if I were you.""" start="00:09:45.740" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""This is EmacsConf.""" start="00:09:48.640" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""We're all hopefully used to writing functional Lisp.""" start="00:09:49.920" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""I would recommend TypeScript or Rust, though,""" start="00:09:53.400" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""depending on your level of performance""" start="00:09:56.240" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""that you really need or whatever language""" start="00:09:58.320" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""you're trying to support ideally.""" start="00:10:00.840" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Most languages have""" start="00:10:02.255" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""some sort of language server protocol already.""" start="00:10:03.400" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""But if they don't, then it might be easier""" start="00:10:06.500" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""to do it in that language.""" start="00:10:09.200" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""TypeScript has a lot of support, a lot of documentation,""" start="00:10:10.160" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""a lot of examples out there""" start="00:10:12.800" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""because it was what Microsoft originally intended""" start="00:10:14.160" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""the language server protocol to be for, for VS Code,""" start="00:10:17.680" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""which is written in TypeScript.""" start="00:10:20.920" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Rust is fast, it's going to take more effort,""" start="00:10:22.080" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""but it's very fast, and Rust Analyzer has a great library""" start="00:10:24.440" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""that they use and that they support.""" start="00:10:28.520" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""So support there, examples there are great.""" start="00:10:30.280" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""The hard part is not really the language server protocol,""" start="00:10:32.800" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""but the actual logic. So, like, if you're doing, like,""" start="00:10:35.840" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""language tooling, you're going to have to do""" start="00:10:39.000" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""analysis on the code, so you need to do parsing,""" start="00:10:40.200" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""possibly compiling, all these different advanced features,""" start="00:10:42.680" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""all these advanced different things.""" start="00:10:47.000" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""For example, Rust Analyzer will do incremental compilation,""" start="00:10:48.960" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""which is really, really cool,""" start="00:10:52.520" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""but that's, like, a whole separate talk.""" start="00:10:54.320" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""If you're adapting an existing language tool,""" start="00:10:58.120" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""this stuff is really easy.""" start="00:11:00.320" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""You're basically just wiring stuff up.""" start="00:11:01.680" video="mainVideo-lspocaml" id="subtitle"]]

Supporting a LS through LSP mode in Emacs

[[!template new="1" text="""But, yeah. So, now we know all about""" start="00:11:03.480" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""LSP and language servers.""" start="00:11:08.360" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Say you want to actually""" start="00:11:10.800" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""add support for a language server in Emacs.""" start="00:11:11.880" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""How do you do that? Well, let's look at LSP mode,""" start="00:11:14.080" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""because, like I said, this is what I'm most familiar with.""" start="00:11:19.160" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""I'm sure `eglot-mode` is pretty similar.""" start="00:11:21.520" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""So, `lsp-mode`'s repository is on GitHub,""" start="00:11:24.260" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""like everything, and it has a ton of different clients""" start="00:11:27.480" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""for a ton of different languages and frameworks and tools,""" start="00:11:31.500" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""like Semgrep, and these are available""" start="00:11:34.440" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""to anyone who installs LSP mode.""" start="00:11:37.040" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Alternatively, you can make a separate package""" start="00:11:39.740" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and just use LSP mode as a library,""" start="00:11:42.240" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""but I'm not going to focus on this,""" start="00:11:43.680" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""because there's already a ton of resources out there""" start="00:11:45.480" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""on packaging and Emacs.""" start="00:11:47.880" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""So, our steps, very quickly, are going to look like""" start="00:11:50.800" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""adding an Emacs Lisp file that contains some logic,""" start="00:11:54.560" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""add an entry somewhere, so we added a new client""" start="00:11:58.300" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""to the list of clients, and then do some documentation,""" start="00:12:01.320" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""because documentation's great.""" start="00:12:03.720" video="mainVideo-lspocaml" id="subtitle"]]

Create a client

[[!template new="1" text="""First, creating a client.""" start="00:12:06.000" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""In the `clients/` folder in `lsp-mode/`,""" start="00:12:07.640" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""literally just add, like, `lsp-` whatever it is,""" start="00:12:09.640" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""`require` the library, and register a client.""" start="00:12:12.920" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Registering a client just means, like,""" start="00:12:15.760" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""saying what kind of connection it is.""" start="00:12:18.040" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""It's most likely going to be standard I/O,""" start="00:12:19.560" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""because that's pretty easy to implement,""" start="00:12:21.480" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and then you just pass it the executable""" start="00:12:24.360" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""that you actually want to run.""" start="00:12:26.840" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Say what the activation function is,""" start="00:12:29.560" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""so this is when the client should start,""" start="00:12:31.720" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""so you can specify the language""" start="00:12:33.320" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""or the major mode or whatever,""" start="00:12:36.240" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and now your client will start whenever that's triggered,""" start="00:12:38.760" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and then finally provide just a server ID,""" start="00:12:43.100" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""so that way it's easy to keep track of,""" start="00:12:45.640" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and then run this LSP consistency check function.""" start="00:12:48.580" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""This just makes sure everything up there is good.""" start="00:12:52.760" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""You can do more advanced stuff with making an LSP client""" start="00:12:56.580" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""that I'm not going to get into,""" start="00:12:59.520" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""but just know that these aren't your only options,""" start="00:13:01.200" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and then finally provide your client.""" start="00:13:03.800" video="mainVideo-lspocaml" id="subtitle"]]

Add to list of client packages

[[!template new="1" text="""Next, you just have to add your client""" start="00:13:07.300" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""to the list of clients that `lsp-mode` supports,""" start="00:13:09.800" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and now you've added support for a whole new language,""" start="00:13:12.160" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""whole new framework, whole new tool to Emacs,""" start="00:13:15.640" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and it's taking you, what, like, what is that,""" start="00:13:17.720" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""20 lines of Lisp? No, not even, like, 15.""" start="00:13:20.220" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""15 lines of Lisp, whole new language for Emacs.""" start="00:13:23.640" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""It's really exciting. Now that you have your client,""" start="00:13:26.640" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""let's do some documentation. Go fill out this, like, name,""" start="00:13:31.600" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""where the repository, the source code is,""" start="00:13:35.120" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""because free software is great,""" start="00:13:37.920" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and you should open source your stuff.""" start="00:13:39.600" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Specify the installation command.""" start="00:13:42.180" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""What's cool about this is""" start="00:13:44.200" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""this can be run automatically from Emacs,""" start="00:13:45.400" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""so if it's, like, `pip install pyright`, right,""" start="00:13:48.060" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""you can put that there, and Emacs will ask you,""" start="00:13:50.320" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""do you want to install the language server,""" start="00:13:53.400" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and you can hit yes""" start="00:13:55.280" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and users will just have it installed for them,""" start="00:13:56.200" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and then you can say whether or not it's a debugger.""" start="00:13:59.540" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""This is completely separate,""" start="00:14:01.880" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""so there's this thing called DAP,""" start="00:14:03.160" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""which is the debugger adapter protocol,""" start="00:14:05.120" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and it's similar to LSP but for debuggers,""" start="00:14:07.320" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""which is very cool,""" start="00:14:09.680" video="mainVideo-lspocaml" id="subtitle"]]

Add documentation!

[[!template new="1" text="""and then finally link to your documentation.""" start="00:14:11.680" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Please, please document your stuff.""" start="00:14:14.600" video="mainVideo-lspocaml" id="subtitle"]]

Adding commands and custom capabilities

[[!template new="1" text="""If you want to add, like, a custom Emacs function""" start="00:14:17.880" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""or custom capabilities, it's super easy.""" start="00:14:20.480" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""It's literally just, like, calling a normal Emacs function.""" start="00:14:22.680" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""For example, Semgrep normally only scans files""" start="00:14:27.640" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""when you open them, but we added a Emacs function""" start="00:14:30.560" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""that will scan your entire project, right,""" start="00:14:34.200" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and so that was just a client notification.""" start="00:14:36.720" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""It was just `lsp-notify` and then a custom method,""" start="00:14:40.960" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and it's great because now you can just scan your project""" start="00:14:44.120" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""from a simple Emacs function.""" start="00:14:46.720" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Requests, very similar to notifications.""" start="00:14:48.720" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""You send it and then pass it a lambda""" start="00:14:52.120" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and do something with the result,""" start="00:14:56.080" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and so that's adding custom capabilities.""" start="00:14:58.460" video="mainVideo-lspocaml" id="subtitle"]]

Thanks for listening

[[!template new="1" text="""That's pretty much it. Thank you for listening.""" start="00:15:01.360" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Some resources here.""" start="00:15:04.320" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""These links are clickable if you get the PDF,""" start="00:15:05.640" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""if you get the slides. Semgrep: we're hiring!""" start="00:15:08.240" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""If you want to work on, like,""" start="00:15:10.920" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""programming language theory stuff,""" start="00:15:12.120" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""compilers, parsers, editors,""" start="00:15:13.720" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""email me or go look at our jobs.""" start="00:15:18.120" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""The LSP specification, this is, like, the holy Bible.""" start="00:15:22.120" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""It has all the specs, all the types, everything.""" start="00:15:25.120" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""`lsp-mode` and the docs.""" start="00:15:28.340" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""`lsp-mode`, right, that's where you want to add your client.""" start="00:15:30.420" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""The docs are great, super useful.""" start="00:15:33.280" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""Rust Analyzer is just a great reference""" start="00:15:36.100" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""for language servers in general""" start="00:15:38.080" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""if you want to write one or if you just want to, like,""" start="00:15:39.920" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""see how they work. It's all just really well done.""" start="00:15:42.120" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""It's great code, very readable.""" start="00:15:45.400" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""And then down here is just a long video tutorial,""" start="00:15:47.040" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""a longer video tutorial, not by me,""" start="00:15:50.480" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""by someone else, on how to add a language client to Emacs,""" start="00:15:54.700" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""but hopefully this is sufficient for y'all,""" start="00:15:58.440" video="mainVideo-lspocaml" id="subtitle"]]
[[!template text="""and now it's time for some Q&A.""" start="00:16:01.480" video="mainVideo-lspocaml" id="subtitle"]]



Captioner: sachac

Questions or comments? Please e-mail [austin@cutedogs.org](mailto:austin@cutedogs.org?subject=Comment%20for%20EmacsConf%202023%20lspocaml%3A%20Writing%20a%20language%20server%20in%20OCaml%20for%20Emacs%2C%20fun%2C%20and%20profit)


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