scohen

Lexical

Lexical is a next-generation language server for the Elixir programming language.

Features

Context aware code completion
As-you-type compilation
Advanced error highlighting
Code actions
Code Formatting
Go To Definition
Completely isolated build environment

What makes Lexical different?

There are a couple things that lexical does differently than other language servers. Let’s look at what separates it from the pack.

When lexical starts, it boots an erlang virtual machine that runs the language server and its code. It then boots a separate virtual machine that runs your project code and connects the two via distribution. This provides the following benefits:

None of lexical’s dependencies will conflict with your project. This means that lexical can make use of dependencies to make developing in it easier without having to “vendor” them. It also means that you can use lexical to work on your project, even if lexical depends on your project.
Your project can depend on a different version of elixir and erlang than lexical itself. This means that lexical can make use of the latest versions of elixir and erlang while still supporting projects that run on older versions.
The build environment for your project is only aware of your project, which enables as-you-type compilation and error reporting.
In the future, there is a possibility of having the lexical vm instance control multiple projects

Lexical 0.4.0 Has been released!

Get it here: Release v0.4.0 · lexical-lsp/lexical · GitHub
Github: GitHub - lexical-lsp/lexical: Lexical is a next-generation elixir language server · GitHub

The main thrust of v0.4 is hover support and quality of life improvements. Now, when you hover over a module or function, you’ll see relevant documentation, types and parameters. We’ve also spent a lot of time working on completions in #410, which makes them more consistent, fixes some bugs in certain language clients (like eglot adding an extra @ when completing module attributes), and greatly improves their feel in vscode.

Additionally, quite a few of the changes in this PR were about laying the groundwork for our indexing infrastructure, which will debut in the next version. But fear not, this version has indexing disabled.

I want to thank @zachallaun and @scottming for all their hard work on this release. They’ve made lexical faster, more friendly and have removed a bunch of bugs!

Highlights include:

Document hover for functions and modules
Improved boot scripts
Automatically updating nix flake. Thanks, @hauleth
Helix editor integration. Thanks @philipgiuliani
.heex integration
Massively improved completions (Check out the PR, it’s too big to summarize)

Bugs fixed:

Longstanding unicode completion / editing bugs slain. Unicode works perfectly now.

78 comments

#library #code-editors #lsp #lexical #lexical-lsp

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2024-12-30 21:17:06 UTC

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Nezteb

I’m stoked for “find references”: Find References by scohen · Pull Request #405 · lexical-lsp/lexical · GitHub

Post #1

jimsynz

Ash Core Team

This sounds awesome. Does Lexical have or plan to have a plug-in system? We (Ash) have an elixir sense plug-in that allows auto completion and documentation for spark DSLs.

Post #2

scohen

Yea, there are plans for a plugin system. We currently have a diagnostics plugin for credo. We also want to make a system for completions. What do you need?

If you want to chat in real time, pop into our discord ( or go to the #editor-tooling channel on the elixir discord)

Post #3

hst337

Is Lexical suitable for large codebases? elixir-ls takes around 5-6 seconds to respond to goto and goto-reference in big projects. Will Lexical be an improvement here?

Post #4

scohen

We’ve taken a different approach for things like find references that should yield an improvement over the strategy taken by elixir-ls, but it’s early days for the feature. We need to improve the performance of the indexer, but we have lots of options, and are optimistic.

To give you an idea, I have a test project that has around 800,000 lines of code, and find references takes 20 milliseconds.

Right now, the bottleneck is indexing, a project that size will take minutes to index, but we’re working on it. it really depends on how large the codebase is. Are we taking about millions of lines? Hundreds of thousands?

Post #5

dimitarvp

Just an idea for you, you could make a separate repo for the indexer and show it to the forum here, and ask for improvement ideas. Do include data as well.

There is a good amount of forum regulars that like to optimize stuff (myself included), plus you really want to get this part right. Might be a very interesting and enlightening community project.

Post #6

scohen

The indexer is fairly isolated code, but breaking it out into a separate repo would be a lot of work due to dependencies. If it’s alright, I can add some benchmarks and point you all to the relevant bits.

We also have ideas about how to improve it that we’re iterating on right now. It’s almost an order of magnitude faster now, and we’ve just fixed the easy stuff.

I suspect that soon, the bottleneck will be elixir’s Code module.

Still, I’d really appreciate more eyes.

Post #7

scohen

It’s also worth noting that the index times are only on the first index. Subsequent indexes will only examine files that have changed in the interim, and will be much faster

Post #8

dimitarvp

Please do, I am sure people would contribute in that format as well.

EDIT: And please make sure external contributors have one or more [code] databases to work with so the benchmarks can all use the same data. Probably goes without saying but figured I’ll make my comment self-contained & full.

Post #9