IdeM (or CodeActionProvider) should give access to the VFS contents

[alanz]

A CodeActionProvider call, and a Plugin Command should have functions along the lines of

getSourceForRange :: Range -> Maybe [Text]

which accesses the current contents of the VFS, and returns the fragment within the given range, if it exists.

The return value could be an list of lines, or a single Text string, whichever makes sense.

[lukel97]

Some comments from IRC for posterity

[12:24am] lukelau: alanz: I was reading that earlier, does brittany do that type of formatting?
[12:25am] lukelau: I agree though, it would be a great example plugin
[12:25am] lukelau: I think the VFS is stored inside haskell-lsp’s LspFuncs
[12:25am] lukelau: Which is only in the reactor monad
[12:27am] lukelau: I feel like a lot more of the stuff inside LspFuncs should be inside IdeM
[12:27am] lukelau: Since CodeActionRequest is already having to manually pass through the project root, which is in LspFuncs
[12:27am] lukelau: And the same goes for client capabilities
[12:28am] lukelau: It would also be nice to have the client config available as well, it would unblock that brittany PR
[12:30am] lukelau: Just from looking at https://hackage.haskell.org/package/haskell-lsp-0.8.0.0/docs/Language-Haskell-LSP-Core.html#t:LspFuncs, everything except for sendFunc, publish/flushDiagnostics and getNextReqId could be in IdeM
[12:32am] lukelau: Maybe we should separate it out into the “internal” functions and stuff that is shared in IdeM
[12:33am] lukelau: To answer your question though, I’ve been using GM.withMappedFile file inside HsImport

[alanz]

This came in via #869