Signature help

[felixfbecker]

https://github.com/Microsoft/language-server-protocol/blob/master/protocol.md#signature-help-request

[vakata]

Hello,

I made a very crude attempt at implementing signature help.

It works well enough for me, but I did not create a PR, because:

1. To improve resolving I had to open the current file and do some seeking: vakata@3b4e0c3#diff-419997c105b8230a20d50dd0d9f907d6R63
2. I had to resort to using some custom token stacking logic on top of the Lexer class in order to find the active parameter which is an ugly hack and not very elegant: vakata@8995611

Still, I thought I'd share, some parts may be useful:
https://github.com/vakata/php-language-server/commits/signatureHelp

[felixfbecker]

Open a PR, it's better to discuss it there :)

[codewp]

Please let me know when this feature comes to VS Code?
I think that this feature is a most used feature by developers.

Thanks.

[felixfbecker]

@codewp there's a subscribe button on the right side