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, g...@git.haskell.org wrote:
Repository : ssh://g...@git.haskell.org/template-haskell
On branch : master
Link :
http://git.haskell.org/packages/template-haskell.git/commitdiff/57b662c3efd8579595c8642fce2d4cd60ba4ec0b
---
commit 57b662c3efd8579595c8642fce2d4cd60ba4ec0b
Author: YoEight yo.ei...@gmail.com
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 e...@cis.upenn.edu
---
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@
-
