Add installation and usage instructions

[jneira]

Checklist:

• Installation
  • Nix (?)
  • From source
• Editor integration
  • vscode
  • vim/neovim
  • sublime
  • atom
  • emacs
  • doom emacs
  • spacemacs (?)
  • kakoune

[alanz]

We should be able to bring the info from hie directly, it honours the same arguments.

lsp-haskell has a customize option for it, setting the path to haskell-language-server-wrapper instead of hie-wrapper in any client should just work.

[jneira]

Yeah, i think one little caveat is hls does not accept the --vomit cli option set by the extension if you choose the verbose mode.

setting the path to haskell-language-server-wrapper instead of hie-wrapper in any client should just work

basically it is the key change, you have to set useCustomHieWrapper to true too

{
    "languageServerHaskell.useCustomHieWrapperPath": "D:\\bin\\haskell-language-server-wrapper.exe",
    "languageServerHaskell.useCustomHieWrapper": true,
    "languageServerHaskell.trace.server": "messages"
}

[jneira]

Now there is a vscode extension release that lets choose the server so it is easier.

[EncodePanda]

I'm about to go through the process this week and I will be documenting all my steps. Eventually, I will push them to this repo as docs.

[sir4ur0n]

@EncodePanda I'll try to save you some time: pay attention to installing haskell-language-server with the same GHC version you use in your project!

I didn't pay attention at first while doing stack install and things blew up rather spectacularly in VSCode afterwards 😄

[jneira]

@sir4ur0n yeah it has to be clearly visible in docs. However, the program should have emit a warning in the output pane and in a popup alert. At least haskell-ide-engine used to do it.

[jneira]

I am porting the installation and configuration instruction from hie.
@EncodePanda i hope that will not be a duplicated effort. A more beginner friendly "Getting started" would be great too.

[theGhostJW]

Would someone coming from hie and using vs code need to uninstall anything first and if so could this be added to the readme?

[fendor]

Good point.
An upgrading/switching section would be a great idea!

To give an immediate answer: no, nothing needs to be uninstalled. You can just install hls and point the vscode plugin to use haskell-language-server in its recent settings addition to switch between hie/ghcide/hls.
However, it might make sense to delete unused binaries of hie since they are quite large (like 120MiB, iirc)