Fractional.hs

{-# LANGUAGE GADTs #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}

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{-# LANGUAGE UndecidableInstances #-}

module Feldspar.Core.Constructs.Fractional
    ( FRACTIONAL (..)
    ) where

import Language.Syntactic
import Language.Syntactic.Constructs.Binding

import Feldspar.Core.Types
import Feldspar.Core.Interpretation
import Feldspar.Core.Constructs.Num

data FRACTIONAL a
  where
    DivFrac :: (Type a, Fractional a) => FRACTIONAL (a :-> a :-> Full a)

instance Semantic FRACTIONAL
  where
    semantics DivFrac = Sem "(/)" (/)

instance Equality FRACTIONAL where equal = equalDefault; exprHash = exprHashDefault
instance Render   FRACTIONAL where renderArgs = renderArgsDefault
instance ToTree   FRACTIONAL
instance Eval     FRACTIONAL where evaluate = evaluateDefault
instance EvalBind FRACTIONAL where evalBindSym = evalBindSymDefault
instance Sharable FRACTIONAL

instance SizeProp (FRACTIONAL :|| Type)
  where
    sizeProp (C' s) = sizePropDefault s

instance AlphaEq dom dom dom env => AlphaEq FRACTIONAL FRACTIONAL dom env
  where
    alphaEqSym = alphaEqSymDefault

instance ( (FRACTIONAL :|| Type) :<: dom
         , (NUM :|| Type) :<: dom
         , OptimizeSuper dom)
      => Optimize (FRACTIONAL :|| Type) dom
  where
    constructFeatOpt (C' DivFrac) (a :* b :* Nil)
        | Just 1 <- viewLiteral b = return a
        | alphaEq a b = return $ literalDecor 1

    constructFeatOpt (C' DivFrac) ((op :$ a :$ b) :* c :* Nil)
        | Just (C' Mul) <- prjF op
        , alphaEq b c
        = return a

    constructFeatOpt (C' DivFrac) ((op :$ a :$ b) :* c :* Nil)
        | Just (C' Mul) <- prjF op
        , alphaEq a c
        = return b

    constructFeatOpt a args = constructFeatUnOpt a args

    constructFeatUnOpt x@(C' _) = constructFeatUnOptDefault x