1
-----------------------------------------------------------------------------
3
-- Module : GHC.Desugar
4
-- Copyright : (c) The University of Glasgow, 2007
5
-- License : see libraries/base/LICENSE
7
-- Maintainer : cvs-ghc@haskell.org
8
-- Stability : internal
9
-- Portability : non-portable (GHC extensions)
11
-- Support code for desugaring in GHC
13
-----------------------------------------------------------------------------
16
module GHC.Desugar ((>>>), AnnotationWrapper(..), toAnnotationWrapper) where
18
import Control.Arrow (Arrow(..))
19
import Control.Category ((.))
20
import Data.Data (Data)
22
-- A version of Control.Category.>>> overloaded on Arrow
24
(>>>) :: forall arr. Arrow arr => forall a b c. arr a b -> arr b c -> arr a c
26
-- NB: the type of this function is the "shape" that GHC expects
27
-- in tcInstClassOp. So don't put all the foralls at the front!
28
-- Yes, this is a bit grotesque, but heck it works and the whole
29
-- arrows stuff needs reworking anyway!
32
-- A wrapper data type that lets the typechecker get at the appropriate dictionaries for an annotation
33
data AnnotationWrapper = forall a. (Data a) => AnnotationWrapper a
35
toAnnotationWrapper :: (Data a) => a -> AnnotationWrapper
36
toAnnotationWrapper what = AnnotationWrapper what