Add Autocomplete with LSP

[ouuan]

Is your feature request related to a problem? Please describe.

QCodeEditor lacks of features like auto-completion, jump to ref and so on.

Describe the solution you'd like

Support language server.

Describe alternatives you've considered

Use scintilla for these features, but scintilla has many limitations, too.

Additional context

N/A

[caretaker-claire]

Hi ouuan
Thanks for Opening a new Issue here. I will also thank you for strictly following the Issue Templates.
I will add an appropriate tag to your Issue.

Have Patience, One of our Cool Contributors will help you soon.

[coder3101]

MasRay's ccls will be best. Its fast and works on very nicely and have everything for C/C++

[coder3101]

Also put these codes in a separate folder like include/lsp/CppLsp.h and similarly for source files.

[coder3101]

I will be making https://github.com/coder3101/lsp-cpp compatible to work with the editor. This would add Simple LSP for Editor. We don't need complex LSP like that of VSCODE because our editor works on single file mode and that is enough.

[coder3101]

QCodeEditor must modify its auto complete insertion text, because for auto completion of functions the LSP responds with text as below:

void foo(int bar);

int main(){
   fo|
}

| Is the cursor.

The LSP responds with following completion text

foo(${bar:int})

Insertion of this line is not valid rather, contents inside {} are for us to know what variable and types are expected, we should rather only complete functional name and braces and place cursor inside of the brace. Something like foo(|)

This preprocessing can be done from LSP client side as well but more preferred place is within insertCompletion() within QCodeEditor.

[madhur4127]

The reason that stops me from using this is clangd.

Clangd being more than a LSP that tightly integrates with the compiler makes programming easy.

[coder3101]

@madhur4127 Could you elaborate your comment?

[coder3101]

There is already LSP support. Even the Client we use currently support everything that LSP offers. It is just that we don't have UI/Code Editor that can show these things.

[h2110100]

Is the auto-completion still under works? I can use linting ok with clangd but I can't see the suggestions.