Integral.hs

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module Feldspar.Core.Frontend.Integral
where

import qualified Prelude as P

import Data.Int
import Data.Word

import Language.Syntactic

import Feldspar.Range
import Feldspar.Core.Types
import Feldspar.Core.Constructs
import Feldspar.Core.Constructs.Integral

import Feldspar.Core.Frontend.Condition
import Feldspar.Core.Frontend.Eq
import Feldspar.Core.Frontend.Logic
import Feldspar.Core.Frontend.Num
import Feldspar.Core.Frontend.Ord

import Feldspar.Core.Frontend.Num

-- TODO Make (Size a ~ Range a) a super-class constraint when going to newer GHC
class (Ord a, Numeric a, BoundedInt a, P.Integral a) => Integral a
  where
    quot :: (Size a ~ Range a) => Data a -> Data a -> Data a
    quot = sugarSym Quot
    rem  :: (Size a ~ Range a) => Data a -> Data a -> Data a
    rem  = sugarSym Rem
    div  :: (Size a ~ Range a) => Data a -> Data a -> Data a
    div  = divSem
    mod  :: (Size a ~ Range a) => Data a -> Data a -> Data a
    mod  = sugarSym Mod
    (^)  :: (Size a ~ Range a) => Data a -> Data a -> Data a
    (^)  = sugarSym Exp

-- TODO: This is a short-term hack because the compiler doesn't compile
-- the Div construct correctly. So we give the semantics of div in terms of
-- quot directly, and never use the Div construct. In the long term the
-- compiler should be fixed, but it involves writing type corrector plugins
-- and this solution was quicker.
divSem x y = (x > 0 && y < 0 || x < 0 && y > 0) && rem x y /= 0 ?
             (quot x y P.- 1,quot x y)

instance Integral Word8
instance Integral Word16
instance Integral Word32
instance Integral Word64
instance Integral WordN
instance Integral Int8
instance Integral Int16
instance Integral Int32
instance Integral Int64
instance Integral IntN