Implement signature help #4626
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| {-# LANGUAGE DataKinds #-} | ||
| {-# LANGUAGE GADTs #-} | ||
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| module Ide.Plugin.SignatureHelp (descriptor) where | ||
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| import Control.Arrow ((>>>)) | ||
| import Data.Bifunctor (bimap) | ||
| import qualified Data.Map.Strict as M | ||
| import Data.Maybe (mapMaybe) | ||
| import qualified Data.Set as S | ||
| import Data.Text (Text) | ||
| import qualified Data.Text as T | ||
| import Development.IDE (GetHieAst (GetHieAst), | ||
| HieAstResult (HAR, hieAst, hieKind), | ||
| HieKind (..), | ||
| IdeState (shakeExtras), | ||
| Pretty (pretty), | ||
| Recorder, WithPriority, | ||
| printOutputable) | ||
| import Development.IDE.Core.PluginUtils (runIdeActionE, | ||
| useWithStaleFastE) | ||
| import Development.IDE.Core.PositionMapping (fromCurrentPosition) | ||
| import Development.IDE.GHC.Compat (ContextInfo (Use), | ||
| FastStringCompat, HieAST, | ||
| HieASTs, | ||
| IdentifierDetails, Name, | ||
| RealSrcSpan, SDoc, | ||
| getAsts, | ||
| getSourceNodeIds, | ||
| hieTypeToIface, | ||
| hie_types, identInfo, | ||
| identType, | ||
| isAnnotationInNodeInfo, | ||
| mkRealSrcLoc, | ||
| mkRealSrcSpan, | ||
| nodeChildren, nodeSpan, | ||
| ppr, recoverFullType, | ||
| smallestContainingSatisfying, | ||
| sourceNodeInfo) | ||
| import Development.IDE.GHC.Compat.Util (LexicalFastString (LexicalFastString)) | ||
| import GHC.Data.Maybe (rightToMaybe) | ||
| import GHC.Types.SrcLoc (isRealSubspanOf) | ||
| import Ide.Plugin.Error (getNormalizedFilePathE) | ||
| import Ide.Types (PluginDescriptor (pluginHandlers), | ||
| PluginId, | ||
| PluginMethodHandler, | ||
| defaultPluginDescriptor, | ||
| mkPluginHandler) | ||
| import Language.LSP.Protocol.Message (Method (Method_TextDocumentSignatureHelp), | ||
| SMethod (SMethod_TextDocumentSignatureHelp)) | ||
| import Language.LSP.Protocol.Types (Null (Null), | ||
| ParameterInformation (ParameterInformation), | ||
| Position (Position), | ||
| SignatureHelp (SignatureHelp), | ||
| SignatureHelpParams (SignatureHelpParams), | ||
| SignatureInformation (SignatureInformation), | ||
| TextDocumentIdentifier (TextDocumentIdentifier), | ||
| UInt, | ||
| type (|?) (InL, InR)) | ||
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| data Log = LogDummy | ||
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| instance Pretty Log where | ||
| pretty = \case | ||
| LogDummy -> "TODO(@linj) remove this dummy log" | ||
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| descriptor :: Recorder (WithPriority Log) -> PluginId -> PluginDescriptor IdeState | ||
| descriptor _recorder pluginId = | ||
| (defaultPluginDescriptor pluginId "Provides signature help of something callable") | ||
| { Ide.Types.pluginHandlers = mkPluginHandler SMethod_TextDocumentSignatureHelp signatureHelpProvider | ||
| } | ||
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| -- TODO(@linj) get doc | ||
| signatureHelpProvider :: PluginMethodHandler IdeState Method_TextDocumentSignatureHelp | ||
| signatureHelpProvider ideState _pluginId (SignatureHelpParams (TextDocumentIdentifier uri) position _mProgreeToken _mContext) = do | ||
| nfp <- getNormalizedFilePathE uri | ||
| mResult <- runIdeActionE "signatureHelp" (shakeExtras ideState) $ do | ||
| -- TODO(@linj) why HAR {hieAst} may have more than one AST? | ||
| (HAR {hieAst, hieKind}, positionMapping) <- useWithStaleFastE GetHieAst nfp | ||
| case fromCurrentPosition positionMapping position of | ||
| Nothing -> pure Nothing | ||
| Just oldPosition -> do | ||
| let functionName = | ||
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| extractInfoFromSmallestContainingFunctionApplicationAst | ||
| oldPosition | ||
| hieAst | ||
| (\span -> getLeftMostNode >>> getNodeName span) | ||
| functionType = | ||
| extractInfoFromSmallestContainingFunctionApplicationAst | ||
| oldPosition | ||
| hieAst | ||
| (\span -> getLeftMostNode >>> getNodeType hieKind span) | ||
| argumentNumber = | ||
| extractInfoFromSmallestContainingFunctionApplicationAst | ||
| oldPosition | ||
| hieAst | ||
| getArgumentNumber | ||
| pure $ Just (functionName, functionType, argumentNumber) | ||
| case mResult of | ||
| -- TODO(@linj) what do non-singleton lists mean? | ||
| Just (functionName : _, functionType : _, argumentNumber : _) -> do | ||
| pure $ InL $ mkSignatureHelp functionName functionType (fromIntegral argumentNumber - 1) | ||
| _ -> pure $ InR Null | ||
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| mkSignatureHelp :: Name -> Text -> UInt -> SignatureHelp | ||
| mkSignatureHelp functionName functionType argumentNumber = | ||
| let functionNameLabelPrefix = printOutputable (ppr functionName) <> " :: " | ||
| in SignatureHelp | ||
| [ SignatureInformation | ||
| (functionNameLabelPrefix <> functionType) | ||
| Nothing | ||
| (Just $ mkArguments (fromIntegral $ T.length functionNameLabelPrefix) functionType) | ||
| (Just $ InL argumentNumber) | ||
| ] | ||
| (Just 0) | ||
| (Just $ InL argumentNumber) | ||
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| -- TODO(@linj) can type string be a multi-line string? | ||
| mkArguments :: UInt -> Text -> [ParameterInformation] | ||
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There was a problem hiding this comment. I think this would be a lot simpler if you were just looking at the type itself! There was a problem hiding this comment. Although hmm, the offsets are into the string 😱 So maybe you would need to incrementally build up the There was a problem hiding this comment. See #4626 (comment) |
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| mkArguments offset functionType = | ||
| let separator = " -> " | ||
| separatorLength = fromIntegral $ T.length separator | ||
| splits = T.breakOnAll separator functionType | ||
| prefixes = fst <$> splits | ||
| prefixLengths = fmap (T.length >>> fromIntegral) prefixes | ||
| ranges = | ||
| [ ( if previousPrefixLength == 0 then 0 else previousPrefixLength + separatorLength, | ||
| currentPrefixLength | ||
| ) | ||
| | (previousPrefixLength, currentPrefixLength) <- zip (0: prefixLengths) prefixLengths | ||
| ] | ||
| in [ ParameterInformation (InR range) Nothing | ||
| | range <- bimap (+offset) (+offset) <$> ranges | ||
| ] | ||
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| extractInfoFromSmallestContainingFunctionApplicationAst :: | ||
| Position -> HieASTs a -> (RealSrcSpan -> HieAST a -> Maybe b) -> [b] | ||
| extractInfoFromSmallestContainingFunctionApplicationAst position hieAsts extractInfo = | ||
| M.elems $ flip M.mapMaybeWithKey (getAsts hieAsts) $ \hiePath hieAst -> | ||
| smallestContainingSatisfying (positionToSpan hiePath position) (nodeHasAnnotation ("HsApp", "HsExpr")) hieAst | ||
| >>= extractInfo (positionToSpan hiePath position) | ||
| where | ||
| positionToSpan hiePath position = | ||
| let loc = mkLoc hiePath position in mkRealSrcSpan loc loc | ||
| mkLoc (LexicalFastString hiePath) (Position line character) = | ||
| mkRealSrcLoc hiePath (fromIntegral line + 1) (fromIntegral character + 1) | ||
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| type Annotation = (FastStringCompat, FastStringCompat) | ||
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| nodeHasAnnotation :: Annotation -> HieAST a -> Bool | ||
| nodeHasAnnotation annotation = sourceNodeInfo >>> maybe False (isAnnotationInNodeInfo annotation) | ||
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| -- TODO(@linj): the left most node may not be the function node. example: (if True then f else g) x | ||
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There was a problem hiding this comment. this is a great example btw. In this case I think we would have to give no signature help, I think, since it's only dynamically known which function we're getting. There was a problem hiding this comment. We have one related test case for this now: the This test is not a unit test for this |
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| getLeftMostNode :: HieAST a -> HieAST a | ||
| getLeftMostNode thisNode = | ||
| case nodeChildren thisNode of | ||
| [] -> thisNode | ||
| leftChild: _ -> getLeftMostNode leftChild | ||
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| getNodeName :: RealSrcSpan -> HieAST a -> Maybe Name | ||
| getNodeName _span hieAst = | ||
| if nodeHasAnnotation ("HsVar", "HsExpr") hieAst | ||
| then | ||
| case mapMaybe extractName $ M.keys $ M.filter isUse $ getSourceNodeIds hieAst of | ||
| [name] -> Just name -- TODO(@linj) will there be more than one name? | ||
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There was a problem hiding this comment. I'm not 100% sure when/if this can happen. I think it might happen if we're looking at a typeclass method, in which case we could get the generic typeclass method and the specific one perhaps? That would be a good use-case for multilple signatures, e.g. if we have then we might want to see both the generic There was a problem hiding this comment. I think my general suggestion would be: let's treat possibly-multiple node annotations as producing possibly-multiple signatures. There was a problem hiding this comment. Implemented in d603ec4. Related tests:
I do not have a principled conclusion. But from my experiments, the summary is that
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| _ -> Nothing | ||
| else Nothing -- TODO(@linj) must function node be HsVar? | ||
| where | ||
| extractName = rightToMaybe | ||
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| -- TODO(@linj) share code with getNodeName | ||
| getNodeType :: HieKind a -> RealSrcSpan -> HieAST a -> Maybe Text | ||
| getNodeType (hieKind :: HieKind a) _span hieAst = | ||
| if nodeHasAnnotation ("HsVar", "HsExpr") hieAst | ||
| then | ||
| case M.elems $ M.filter isUse $ getSourceNodeIds hieAst of | ||
| [identifierDetails] -> identType identifierDetails >>= (prettyType >>> Just) | ||
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There was a problem hiding this comment. I suggest not printing the type here and instead returning the type itself. That would mean that when you're doing There was a problem hiding this comment. See #4626 (comment) |
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| _ -> Nothing -- TODO(@linj) will there be more than one identifierDetails? | ||
| else Nothing | ||
| where | ||
| -- modified from Development.IDE.Spans.AtPoint.atPoint | ||
| prettyType :: a -> Text | ||
| prettyType = expandType >>> printOutputable | ||
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| expandType :: a -> SDoc | ||
| expandType t = case hieKind of | ||
| HieFresh -> ppr t | ||
| HieFromDisk hieFile -> ppr $ hieTypeToIface $ recoverFullType t (hie_types hieFile) | ||
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| isUse :: IdentifierDetails a -> Bool | ||
| isUse = identInfo >>> S.member Use | ||
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| -- Just 1 means the first argument | ||
| getArgumentNumber :: RealSrcSpan -> HieAST a -> Maybe Integer | ||
| getArgumentNumber span hieAst = | ||
| if nodeHasAnnotation ("HsApp", "HsExpr") hieAst | ||
| then | ||
| case nodeChildren hieAst of | ||
| [leftChild, _] -> | ||
| if span `isRealSubspanOf` nodeSpan leftChild | ||
| then Nothing | ||
| else getArgumentNumber span leftChild >>= \argumentNumber -> Just (argumentNumber + 1) | ||
| _ -> Nothing -- impossible | ||
| else | ||
| case nodeChildren hieAst of | ||
| [] -> Just 0 -- the function is found | ||
| [child] -> getArgumentNumber span child -- ignore irrelevant nodes | ||
| _ -> Nothing -- TODO(@linj) handle more cases such as `if` | ||
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I think this is reasonable. Really
combineResponsesshould have a way to return an error. There are a bunch of methods where it really only makes sense if we have one handler.We could try to combine responses: we would combine the signatures, and so long as only one of them indicated an active signature it would be okay. But that's a bit sketchy and I doubt we'll have several anyway!