Re: [commit: packages/template-haskell] master: Make Pred a type synonym of Type (issue #7021) (57b662c)

What's the right way to fix libraries (e.g. aeson) that break because classP was removed? On Mon, Feb 10, 2014 at 2:39 AM, wrote:

Repository : ssh://git@git.haskell.org/template-haskell

On branch : master Link : http://git.haskell.org/packages/template-haskell.git/commitdiff/57b662c3efd8...

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commit 57b662c3efd8579595c8642fce2d4cd60ba4ec0b Author: YoEight Date: Fri Jan 10 21:42:01 2014 +0100

Make Pred a type synonym of Type (issue #7021)

In order to make any type as a Predicate in Template Haskell, as allowed by ConstraintKinds

Signed-off-by: Richard Eisenberg

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57b662c3efd8579595c8642fce2d4cd60ba4ec0b Language/Haskell/TH.hs | 7 +++---- Language/Haskell/TH/Lib.hs | 21 ++++++++------------- Language/Haskell/TH/Ppr.hs | 8 ++------ Language/Haskell/TH/Syntax.hs | 6 ++---- 4 files changed, 15 insertions(+), 27 deletions(-)

diff --git a/Language/Haskell/TH.hs b/Language/Haskell/TH.hs index 2ab19bd..e9765a9 100644 --- a/Language/Haskell/TH.hs +++ b/Language/Haskell/TH.hs @@ -68,7 +68,7 @@ module Language.Haskell.TH( -- ** Patterns Pat(..), FieldExp, FieldPat, -- ** Types - Type(..), TyVarBndr(..), TyLit(..), Kind, Cxt, Pred(..), Syntax.Role(..), + Type(..), TyVarBndr(..), TyLit(..), Kind, Cxt, Pred, Syntax.Role(..),

-- * Library functions -- ** Abbreviations @@ -105,14 +105,14 @@ module Language.Haskell.TH( bindS, letS, noBindS, parS,

-- *** Types - forallT, varT, conT, appT, arrowT, listT, tupleT, sigT, litT, + forallT, varT, conT, appT, arrowT, equalityT, listT, tupleT, sigT, litT, promotedT, promotedTupleT, promotedNilT, promotedConsT, -- **** Type literals numTyLit, strTyLit, -- **** Strictness isStrict, notStrict, strictType, varStrictType, -- **** Class Contexts - cxt, classP, equalP, normalC, recC, infixC, forallC, + cxt, normalC, recC, infixC, forallC,

-- *** Kinds varK, conK, tupleK, arrowK, listK, appK, starK, constraintK, @@ -146,4 +146,3 @@ module Language.Haskell.TH( import Language.Haskell.TH.Syntax as Syntax import Language.Haskell.TH.Lib import Language.Haskell.TH.Ppr - diff --git a/Language/Haskell/TH/Lib.hs b/Language/Haskell/TH/Lib.hs index b7a88d6..17e794b 100644 --- a/Language/Haskell/TH/Lib.hs +++ b/Language/Haskell/TH/Lib.hs @@ -466,19 +466,6 @@ tySynEqn lhs rhs = cxt :: [PredQ] -> CxtQ cxt = sequence

-classP :: Name -> [TypeQ] -> PredQ -classP cla tys - = do - tys1 <- sequence tys - return (ClassP cla tys1) - -equalP :: TypeQ -> TypeQ -> PredQ -equalP tleft tright - = do - tleft1 <- tleft - tright1 <- tright - return (EqualP tleft1 tright1) - normalC :: Name -> [StrictTypeQ] -> ConQ normalC con strtys = liftM (NormalC con) $ sequence strtys

@@ -536,6 +523,14 @@ sigT t k t' <- t return $ SigT t' k

+equalityT :: TypeQ -> TypeQ -> TypeQ +equalityT tleft tright + = do + tleft1 <- tleft + tright1 <- tright + let typ = AppT (AppT EqualityT tleft1) tright1 + return typ + promotedT :: Name -> TypeQ promotedT = return . PromotedT

diff --git a/Language/Haskell/TH/Ppr.hs b/Language/Haskell/TH/Ppr.hs index 2023f3a..e237066 100644 --- a/Language/Haskell/TH/Ppr.hs +++ b/Language/Haskell/TH/Ppr.hs @@ -496,6 +496,8 @@ instance Ppr Type where

pprTyApp :: (Type, [Type]) -> Doc pprTyApp (ArrowT, [arg1,arg2]) = sep [pprFunArgType arg1 <+> text "->", ppr arg2] +pprTyApp (EqualityT, [arg1, arg2]) = + sep [pprFunArgType arg1 <+> text "~", ppr arg2] pprTyApp (ListT, [arg]) = brackets (ppr arg) pprTyApp (TupleT n, args) | length args == n = parens (sep (punctuate comma (map ppr args))) @@ -540,11 +542,6 @@ pprCxt [t] = ppr t <+> text "=>" pprCxt ts = parens (sep $ punctuate comma $ map ppr ts) <+> text "=>"

------------------------------ -instance Ppr Pred where - ppr (ClassP cla tys) = ppr cla <+> sep (map pprParendType tys) - ppr (EqualP ty1 ty2) = pprFunArgType ty1 <+> char '~' <+> pprFunArgType ty2 - ------------------------------- instance Ppr Range where ppr = brackets . pprRange where pprRange :: Range -> Doc @@ -569,4 +566,3 @@ hashParens d = text "(# " <> d <> text " #)"

quoteParens :: Doc -> Doc quoteParens d = text "'(" <> d <> text ")" - diff --git a/Language/Haskell/TH/Syntax.hs b/Language/Haskell/TH/Syntax.hs index 3606f9d..17bb065 100644 --- a/Language/Haskell/TH/Syntax.hs +++ b/Language/Haskell/TH/Syntax.hs @@ -1346,9 +1346,7 @@ data AnnTarget = ModuleAnnotation

type Cxt = [Pred] -- ^ @(Eq a, Ord b)@

-data Pred = ClassP Name [Type] -- ^ @Eq (Int, a)@ - | EqualP Type Type -- ^ @F a ~ Bool@ - deriving( Show, Eq, Data, Typeable ) +type Pred = Type

data Strict = IsStrict | NotStrict | Unpacked deriving( Show, Eq, Data, Typeable ) @@ -1373,6 +1371,7 @@ data Type = ForallT [TyVarBndr] Cxt Type -- ^ @forall \. \ -> \@ + | EqualityT -- ^ @~@ | ListT -- ^ @[]@ | PromotedTupleT Int -- ^ @'(), '(,), '(,,), etc.@ | PromotedNilT -- ^ @'[]@ @@ -1453,4 +1452,3 @@ cmpEq _ = False thenCmp :: Ordering -> Ordering -> Ordering thenCmp EQ o2 = o2 thenCmp o1 _ = o1 -

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