diff options
author | Tim Baumann <tim@timbaumann.info> | 2017-08-06 11:33:38 +0200 |
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committer | Alexander Biehl <alexbiehl@gmail.com> | 2017-08-06 11:33:38 +0200 |
commit | 3fddb62913c72f29843335aa796c2e444ded1608 (patch) | |
tree | a3cccdacd8e546e527488009ebd5d9c815be46d3 /haddock-api/src/Haddock/Interface | |
parent | 4d765e3cd0a735f9a7e8d13fb6633f9ee534fbfb (diff) |
Fix: Generate pattern signatures for constructors exported as patterns (#663)
* Fix pretty-printing of pattern signatures
Pattern synonyms can have up to two contexts, both having a
different semantic meaning: The first holds the constraints
required to perform the matching, the second contains the
constraints provided by a successful pattern match. When the
first context is empty but the second is not it is necessary
to render the first, empty context.
* Generate pattern synonym signatures for ctors exported as patterns
This fixes #653.
* Simplify extractPatternSyn
It is not necessary to generate the simplest type signature since
it will be simplified when pretty-printed.
* Add changelog entries for PR #663
* Fix extractPatternSyn error message
Diffstat (limited to 'haddock-api/src/Haddock/Interface')
-rw-r--r-- | haddock-api/src/Haddock/Interface/Create.hs | 34 |
1 files changed, 33 insertions, 1 deletions
diff --git a/haddock-api/src/Haddock/Interface/Create.hs b/haddock-api/src/Haddock/Interface/Create.hs index b9179d11..89f7f71b 100644 --- a/haddock-api/src/Haddock/Interface/Create.hs +++ b/haddock-api/src/Haddock/Interface/Create.hs @@ -985,7 +985,9 @@ extractDecl name decl O.$$ O.nest 4 (O.ppr matches)) TyClD d@DataDecl {} -> let (n, tyvar_tys) = (tcdName d, lHsQTyVarsToTypes (tyClDeclTyVars d)) - in SigD <$> extractRecSel name n tyvar_tys (dd_cons (tcdDataDefn d)) + in if isDataConName name + then SigD <$> extractPatternSyn name n tyvar_tys (dd_cons (tcdDataDefn d)) + else SigD <$> extractRecSel name n tyvar_tys (dd_cons (tcdDataDefn d)) InstD (DataFamInstD DataFamInstDecl { dfid_tycon = L _ n , dfid_pats = HsIB { hsib_body = tys } , dfid_defn = defn }) -> @@ -1003,6 +1005,36 @@ extractDecl name decl _ -> error "internal: extractDecl (ClsInstD)" _ -> error "internal: extractDecl" +extractPatternSyn :: Name -> Name -> [LHsType Name] -> [LConDecl Name] -> LSig Name +extractPatternSyn nm t tvs cons = + case filter matches cons of + [] -> error "extractPatternSyn: constructor pattern not found" + con:_ -> extract <$> con + where + matches :: LConDecl Name -> Bool + matches (L _ con) = nm `elem` (unLoc <$> getConNames con) + extract :: ConDecl Name -> Sig Name + extract con = + let args = + case getConDetails con of + PrefixCon args' -> args' + RecCon (L _ fields) -> cd_fld_type . unLoc <$> fields + InfixCon arg1 arg2 -> [arg1, arg2] + typ = longArrow args (data_ty con) + typ' = + case con of + ConDeclH98 { con_cxt = Just cxt } -> noLoc (HsQualTy cxt typ) + _ -> typ + typ'' = noLoc (HsQualTy (noLoc []) typ') + in PatSynSig [noLoc nm] (mkEmptyImplicitBndrs typ'') + + longArrow :: [LHsType name] -> LHsType name -> LHsType name + longArrow inputs output = foldr (\x y -> noLoc (HsFunTy x y)) output inputs + + data_ty con + | ConDeclGADT{} <- con = hsib_body $ con_type con + | otherwise = foldl' (\x y -> noLoc (HsAppTy x y)) (noLoc (HsTyVar NotPromoted (noLoc t))) tvs + extractRecSel :: Name -> Name -> [LHsType Name] -> [LConDecl Name] -> LSig Name extractRecSel _ _ _ [] = error "extractRecSel: selector not found" |