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|
{-# LANGUAGE Trustworthy #-}
{-# LANGUAGE CPP
, NoImplicitPrelude
, Rank2Types
, ExistentialQuantification
#-}
-----------------------------------------------------------------------------
-- |
-- Module : GHC.Desugar
-- Copyright : (c) The University of Glasgow, 2007
-- License : see libraries/base/LICENSE
--
-- Maintainer : cvs-ghc@haskell.org
-- Stability : internal
-- Portability : non-portable (GHC extensions)
--
-- Support code for desugaring in GHC
--
-----------------------------------------------------------------------------
-- #hide
module GHC.Desugar ((>>>), AnnotationWrapper(..), toAnnotationWrapper) where
import Control.Arrow (Arrow(..))
import Control.Category ((.))
import Data.Data (Data)
-- A version of Control.Category.>>> overloaded on Arrow
#ifndef __HADDOCK__
(>>>) :: forall arr. Arrow arr => forall a b c. arr a b -> arr b c -> arr a c
#endif
-- NB: the type of this function is the "shape" that GHC expects
-- in tcInstClassOp. So don't put all the foralls at the front!
-- Yes, this is a bit grotesque, but heck it works and the whole
-- arrows stuff needs reworking anyway!
f >>> g = g . f
-- A wrapper data type that lets the typechecker get at the appropriate dictionaries for an annotation
data AnnotationWrapper = forall a. (Data a) => AnnotationWrapper a
toAnnotationWrapper :: (Data a) => a -> AnnotationWrapper
toAnnotationWrapper what = AnnotationWrapper what
|
