[Feature] Provide Stan integration

[sir4ur0n]

I propose HLS supports Stan integration, what do you think?

[Ailrun]

I think it would be great if possible, but as they use .hie file, we cannot use them for GHC < 8.8...

P.S. You are at the Haskell Love Conference, aren't you? :)

[sir4ur0n]

P.S. You are at the Haskell Love Conference, aren't you? :)

Yes, and I wanted to link the existing HLS-Stan integration issue to others. That's how I noticed there is no issue yet 😛

[fendor]

Hi, I started with this, but have no particular branch yet.
I once had a somewhat working impl, but we need haskell/ghcide#701, too.

[googleson78]

haskell/ghcide#701 is now in hls master, what additional work needs to be done to get this working? @fendor

[jneira]

A required step for sure would be create a plugin to provide stan diagnostics and refactorings (?). I think hls-hlint-plugin could be a good starting point.

[googleson78]

I was wondering if @fendor s work is something that's "almost done", and just needs a bit of cleanup.

[fendor]

@googleson78 The work got stalled, and it was not that much, so we should rather re-write it. I don't have anything workable at the moment :(

[uhbif19]

I will try to work on this.

As far as I understand, it required to add new Rule, which will call Stan runAnalysis for each project file.

[fendor]

Right, but ideally we re-use the .HIE files HLS is already generating, so we save some work.

[uhbif19]

@fendor @jneira

Stan requires HieTypes.HieFile while HLS GetHieAst returns HieAstResult, which contains only Module, not the whole file.
Is there any way to get HieTypes.HieFile out of HLS?

[pepeiborra]

HLS writes .hie files to disk, so you can definitely get a HieFile out of HLS by replicating the existing logic.
Something like this should do it:

getHieFile :: NormalizedFilePath -> Action (Maybe HieFile)
getHieFile nfp = runMaybeT $ do
    HAR{hieAst} <- MaybeT $ use GetHieAst nfp
    tmr <- MaybeT $ use TypeCheck nfp
    ghc <- MaybeT $ use GhcSession nfp
    msr <- MaybeT $ use GetModSummaryWithoutTimestamps nfp
    source <- lift $ getSourceFileSource nfp
    let exports = tcg_exports $ tmrTypechecked tmr
    typedAst <- MaybeT $ pure $ cast hieAst
    liftIO $ runHsc (hscEnv ghc) $ mkHieFile' (msrModSummary msr) exports typedAst source

[uhbif19]

@pepeiborra

Got error:

src/Ide/Plugin/Stan.hs:68:33: error:
    • No instance for (Typeable a) arising from a use of ‘cast’
    • In the second argument of ‘($)’, namely ‘cast hieAst’
      In the second argument of ‘($)’, namely ‘pure $ cast hieAst’
      In a stmt of a 'do' block: typedAst <- MaybeT $ pure $ cast hieAst
   |
68 |     typedAst <- MaybeT $ pure $ cast hieAst
   |                                 ^^^^^^^^^^^

[pepeiborra]

Add a Typeable constraint in the HAR constructor of the HieAstResult data type

[uhbif19]

@pepeiborra Thank you very much, your code worked.

Created WIP PR.