Support for ctags?

[cdecompilador]

[the-mikedavis]

There currently isn't an integration.

The symbol picker from LSP is very similar in nature. As a fallback we could use tree-sitter tags as a naive implementation to do this and stack-graphs (once stabilized) for better accuracy: #1252

IMO ctags could be a plugin rather than a core feature.

[ndcontini]

Even languages that have good LSP support would still benefit from ctag and cscope support. For C/C++ the helix symbol support relies heavily on a) systems having clangd installed, which is problematic if the system you are developing on doesn't have it installed b) providing a compile_commands.json, which is problematic because not all build systems provide this natively c) some projects have multiple valid configurations, so even if I can generate the compile_commands.json, it is tedious to construct it so that each configurations's symbols are included.

For example, I work in HPC, where each cluster I work on is unlikely to have clang installed (in fact I can think of only one that does). The project I'm working on using automake, so I have to use compiledb to generate the compile_commands.json. The build for this project is not well setup, so make -Bn will actually cause ./configure to be called, which will trigger rebuilds that take a long time to run. Finally, the project can be configured in more than 6 different ways, and that number is likely to increase. All the symbol searching and what not works excellently once set up, but the setup itself is a productivity destroyer. Simply running ctags and cscope over the project is on the order of second rather than tens of minutes, so it is a much more lightweight solution. It may not be as robust, but it allows developers to move quickly if they want to navigate code without building it.

[the-mikedavis]

What do you use ctags for specifically? (For example looking up function definitions / macros?) I experimented with recreating LSP features like document and workspace symbol pickers using only tree-sitter queries, actually specifically to work around setting up clangd: https://asciinema.org/a/642876. With that we could provide LSP-like features out of the box when no language server is installed with the tradeoff that it's not as accurate as what a language server would give since it's only an analysis of the syntax.

[ndcontini]

Yeah, I use ctags for finding definitions and cscope for finding references within a project. Basically in vim I'd c-] to trace code and use :tselect if the wrong definition was selected. Then :pop to do up the stack. Helix approximates this with its LSP support, but if you can't set up the LSP support well, then you're stuck doing global search. Then when I need to find where a symbol is declared, initialized, assigned, etc. I'd use cs find s <symbol> and have all the matches sent to the quickfix window. gr in helix does a decent job, again with the caveat that the LSP needs to be set up well.

It sounds like your solution might resolve some of my issues.

[EricHenry]

@the-mikedavis I work on embedded devices and computers with limited resources. LSPs end up being pretty heavy on those systems (especially rust-analyzer). I will use ctags and cscopes for quick jumping to definitions and finding references. Having the ability to jump to definition without an LSP would be a huge. Honestly, even if its less accurate or can't jump into std libs, it would still be a very large productivity increase.

If you'd be up for providing a bit of direction, and discuss your thoughts on the feature, I'd love to contribute.

[the-mikedavis]

The changes involved are not very involved but the current implementation I have (the-mikedavis@1a31fe9) builds on some other changes that I think we should land first. In particular we're working on new tree-sitter bindings (#10286) and a new highlighter and query API that will allow running queries like this across injections. I'm about to be away for a few weeks but when I return I'll write up an idea discussion about how it should work

[rahil627]

dang, i just ran into ctags, for the first time ever. ctags for emacs and vim are provided for a specific game scripting language/run-time: dragonruby, a fork of mruby. 😢 i guess because the main game engine dev uses emacs, they never bothered with a lsp...?? though, to their credit, it's a really simple api, in which ctags is actually the perfect simpler solution here. i know i def wouldn't want to upkeep an lsp, in addition to a cross-platform game engine, and a language run-time.