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

--
-- Copyright (c) 2009-2011, ERICSSON AB
-- All rights reserved.
--
-- Redistribution and use in source and binary forms, with or without
-- modification, are permitted provided that the following conditions are met:
--
--     * Redistributions of source code must retain the above copyright notice,
--       this list of conditions and the following disclaimer.
--     * Redistributions in binary form must reproduce the above copyright
--       notice, this list of conditions and the following disclaimer in the
--       documentation and/or other materials provided with the distribution.
--     * Neither the name of the ERICSSON AB nor the names of its contributors
--       may be used to endorse or promote products derived from this software
--       without specific prior written permission.
--
-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
-- AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-- IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
-- DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
-- FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
-- DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
-- SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
-- CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
-- OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-- OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
--

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 "(/)" (/)

semanticInstances ''FRACTIONAL

instance EvalBind FRACTIONAL where evalBindSym = evalBindSymDefault

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

instance Sharable FRACTIONAL

instance Monotonic FRACTIONAL

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 opts a args = constructFeatUnOpt opts a args

    constructFeatUnOpt opts x@(C' _) = constructFeatUnOptDefault opts x