Getting documentation programmatically?

If you are looking for something more lightweight than a full language server than you could try elixir_sense, the lib utilised by elixirLS - elixir_sense/lib/elixir_sense.ex at 28f8467a349c6ed004aac66a2e8d7020cdde2e0d · elixir-lsp/elixir_sense · GitHub

Yes, I am aware of it and I’m using it, it’s a fantastic tool.

That’s the plan, I am working through the guide right now and I want to try my hands at something useful next. Plus, I prefer reading documentation in a separate buffer I can have open to the side rather than a floating window. I could have probably hacked something using the Lua API of the built-in client, but this seems more interesting. Plus it would work even without a language server running.

I just wanted to make sure you’re aware that there are existing ElixirLS-powered vim/neovim extension that already support fetching Elixir documentation:

• GitHub - prabirshrestha/vim-lsp: async language server protocol plugin for vim and neovim · GitHub
• GitHub - elixir-lsp/coc-elixir: Elixir language server extension based on elixir-ls for coc.nvim · GitHub
• GitHub - neoclide/coc.nvim: Nodejs extension host for vim & neovim, load extensions like VSCode and host language servers. · GitHub

But if you want to create to create this extension for learning purposes, or as an improvement (such as being lighter-weight), then please go ahead

You can use Kernel, no need for cumbersome and non-standard :'Elixir.Kernel'. Btw Kernel is an alias that resolves to :"Elixir.Kernel". :Kernel is just an atom.

iex(2)> :"Elixir.Kernel"
Kernel
iex(3)> :Kernel
:Kernel

You can have a look at ExDoc source code, paritcularly to the retriever module.
https://github.com/elixir-lang/ex_doc/blob/master/lib/ex_doc/retriever.ex

Other Elixir modules of interest are:

• Code: elixir/lib/elixir/lib/code.ex at main · elixir-lang/elixir · GitHub
• Code.Typespec (it is private though): elixir/lib/elixir/lib/code/typespec.ex at main · elixir-lang/elixir · GitHub
• IEx.Introspection: (also private) elixir/lib/iex/lib/iex/introspection.ex at main · elixir-lang/elixir · GitHub

Have fun!

Great, that works! Code.fetch_docs(:'Elixir.Kernel') gives me structured data which I can work with. One more question, how do I specify a function? I have tried Code.fetch_docs(:'Elixir.Kernel.is_atom/1'), but I get {:error, :module_not_found}, same thing without the /1 part.

EDIT: Never mind, I need to look at the implementation of Ex.Introspection.h/1, not Ex.Introspection.h/1.

:Kernel is not the same as Kernel. Kernel is the same as :'Elixir.Kernel'. Try IEx.Introspection.h(Kernel)

Thanks, that looks like what I need. I tried calling it by hand, but I get an error instead:

iex(10)> IEx.Introspection.h(:Kernel)
Could not load module :Kernel, got: nofile
iex(11)> Code.ensure_loaded(:Kernel)
{:error, :nofile}

I looked up the definition of h, but it uses macros, which I am not yet familiar with.

Take a look at h implementation: elixir/lib/iex/lib/iex/introspection.ex at d8d89b431e197dd230ce01bc20f4656d9ef24e5c · elixir-lang/elixir · GitHub

It seems to be using Code.fetch_docs underneath