[nvim.completion] Signature help for overloads

[sohamshanbhag]

Contributing guidelines

• [x] I have read CONTRIBUTING.md
• [x] I have read CODE_OF_CONDUCT.md

Module(s)

mini.completion

Description

Since https://github.com/neovim/neovim/pull/33646, neovim(stable) supports multiple signatures in signature help. This is beneficial for overloads in C/C++. This can be triggered with <C-S> as explained in :h news. Since mini.completion supports signatures out of the box, would it be possible to integrate multiple signatures? Right now, if I type a function, and then <C-S>, there are two signature_help windows, one by nvim and one by mini.completion.

Thanks for the plugin!

[echasnovski]

Thanks for the suggestion!

The initial idea of a signature window is to have a one-line (possibly wrapped) signature. I'll take a look if automatically showing all signatures is possible with concise adjustments. Having a mapping that cycles through possible signatures is probably off the table.

To make it easier in the future, would you mind posting as small as possible code example (presumably in C/C++ with clangd) and position at which there should be more than one signature. That'll greatly help in testing.

[sohamshanbhag]

This feature will be beneficial to all languages which allow function overloading. See the attached example.

#include <string>

int func(int a) { // func 1
    return a;
}

int func(int a, int b) { // func 2
    return a + b;
}

std::string func(std::string abs) { // func 3
    return abs;
}

int main() {
    func(1, 2); // Cursor after (
}

Pressing <C-s> at (_1 should show the behaviour I mentioned. mini.completion already changes the signature help if the number of parameters increases. For example, try

func(1
func("s
func(1, 2

and see that the signature for when , is input changes to func 3. Ideally, the signature when "s is input should also change to func 2, but I understand that may be a substantial change. In this case though, just showing the possible overloads is enough.

Also, I think either cycling or showing all signatures, both are acceptable, so feel free to look into whichever is easier.

Edit: Just to clarify, the three signatures by clangd are

func(int a) -> int
func(std::string abs) -> std::string
func(int a, int b) -> int

[echasnovski]

Thank you so much! I do see now how this might work. This helps a lot.