diff options
| author | Richard Eisenberg <eir@cis.upenn.edu> | 2015-12-24 14:33:19 -0500 |
|---|---|---|
| committer | Richard Eisenberg <eir@cis.upenn.edu> | 2015-12-24 14:37:39 -0500 |
| commit | 2db18b8135335da2da9918b722699df684097be9 (patch) | |
| tree | 660dd90916aa6568694bbe39cdab83c7af98c5d7 /compiler/hsSyn/HsUtils.hs | |
| parent | 48db13d279d592ed3044cbaf3513854bcb0d3dce (diff) | |
| download | haskell-2db18b8135335da2da9918b722699df684097be9.tar.gz | |
Visible type application
This re-working of the typechecker algorithm is based on
the paper "Visible type application", by Richard Eisenberg,
Stephanie Weirich, and Hamidhasan Ahmed, to be published at
ESOP'16.
This patch introduces -XTypeApplications, which allows users
to say, for example `id @Int`, which has type `Int -> Int`. See
the changes to the user manual for details.
This patch addresses tickets #10619, #5296, #10589.
Diffstat (limited to 'compiler/hsSyn/HsUtils.hs')
| -rw-r--r-- | compiler/hsSyn/HsUtils.hs | 26 |
1 files changed, 22 insertions, 4 deletions
diff --git a/compiler/hsSyn/HsUtils.hs b/compiler/hsSyn/HsUtils.hs index 9e8ea9af25..9576197b88 100644 --- a/compiler/hsSyn/HsUtils.hs +++ b/compiler/hsSyn/HsUtils.hs @@ -25,7 +25,7 @@ module HsUtils( mkHsWrap, mkLHsWrap, mkHsWrapCo, mkHsWrapCoR, mkLHsWrapCo, mkHsDictLet, mkHsLams, mkHsOpApp, mkHsDo, mkHsComp, mkHsWrapPat, mkHsWrapPatCo, - mkLHsPar, mkHsCmdCast, + mkLHsPar, mkHsCmdWrap, mkLHsCmdWrap, isLHsTypeExpr_maybe, isLHsTypeExpr, nlHsTyApp, nlHsTyApps, nlHsVar, nlHsLit, nlHsApp, nlHsApps, nlHsIntLit, nlHsVarApps, nlHsDo, nlHsOpApp, nlHsLam, nlHsPar, nlHsIf, nlHsCase, nlList, @@ -445,6 +445,21 @@ nlHsFunTy a b = noLoc (HsFunTy a b) nlHsTyConApp :: name -> [LHsType name] -> LHsType name nlHsTyConApp tycon tys = foldl nlHsAppTy (nlHsTyVar tycon) tys +-- | Extract a type argument from an HsExpr, with the list of wildcards in +-- the type +isLHsTypeExpr_maybe :: LHsExpr name -> Maybe (LHsWcType name) +isLHsTypeExpr_maybe (L _ (HsPar e)) = isLHsTypeExpr_maybe e +isLHsTypeExpr_maybe (L _ (HsType ty)) = Just ty + -- the HsTypeOut case is ill-typed. We never need it here anyway. +isLHsTypeExpr_maybe _ = Nothing + +-- | Is an expression a visible type application? +isLHsTypeExpr :: LHsExpr name -> Bool +isLHsTypeExpr (L _ (HsPar e)) = isLHsTypeExpr e +isLHsTypeExpr (L _ (HsType _)) = True +isLHsTypeExpr (L _ (HsTypeOut _)) = True +isLHsTypeExpr _ = False + {- Tuples. All these functions are *pre-typechecker* because they lack types on the tuple. @@ -609,9 +624,12 @@ mkHsWrapCoR co e = mkHsWrap (mkWpCastR co) e mkLHsWrapCo :: TcCoercionN -> LHsExpr id -> LHsExpr id mkLHsWrapCo co (L loc e) = L loc (mkHsWrapCo co e) -mkHsCmdCast :: TcCoercion -> HsCmd id -> HsCmd id -mkHsCmdCast co cmd | isTcReflCo co = cmd - | otherwise = HsCmdCast co cmd +mkHsCmdWrap :: HsWrapper -> HsCmd id -> HsCmd id +mkHsCmdWrap w cmd | isIdHsWrapper w = cmd + | otherwise = HsCmdWrap w cmd + +mkLHsCmdWrap :: HsWrapper -> LHsCmd id -> LHsCmd id +mkLHsCmdWrap w (L loc c) = L loc (mkHsCmdWrap w c) mkHsWrapPat :: HsWrapper -> Pat id -> Type -> Pat id mkHsWrapPat co_fn p ty | isIdHsWrapper co_fn = p |