{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE TypeFamilies #-}

-- | A sequential representation.
module Futhark.IR.Seq
  ( Seq,

    -- * Simplification
    simplifyProg,

    -- * Module re-exports
    module Futhark.IR.Prop,
    module Futhark.IR.Traversals,
    module Futhark.IR.Pretty,
    module Futhark.IR.Syntax,
  )
where

import Futhark.Builder
import Futhark.Construct
import Futhark.IR.Pretty
import Futhark.IR.Prop
import Futhark.IR.Syntax
import Futhark.IR.Traversals
import qualified Futhark.Optimise.Simplify as Simplify
import qualified Futhark.Optimise.Simplify.Engine as Engine
import Futhark.Optimise.Simplify.Rules
import Futhark.Pass
import qualified Futhark.TypeCheck as TypeCheck

-- | The phantom type for the Seq representation.
data Seq

instance RepTypes Seq where
  type Op Seq = ()

instance ASTRep Seq where
  expTypesFromPat = return . expExtTypesFromPat

instance TypeCheck.CheckableOp Seq where
  checkOp = pure

instance TypeCheck.Checkable Seq

instance Buildable Seq where
  mkBody = Body ()
  mkExpPat idents _ = basicPat idents
  mkExpDec _ _ = ()
  mkLetNames = simpleMkLetNames

instance BuilderOps Seq

instance TraverseOpStms Seq where
  traverseOpStms _ = pure

instance PrettyRep Seq

instance BuilderOps (Engine.Wise Seq)

instance TraverseOpStms (Engine.Wise Seq) where
  traverseOpStms _ = pure

simpleSeq :: Simplify.SimpleOps Seq
simpleSeq = Simplify.bindableSimpleOps (const $ pure ((), mempty))

-- | Simplify a sequential program.
simplifyProg :: Prog Seq -> PassM (Prog Seq)
simplifyProg = Simplify.simplifyProg simpleSeq standardRules blockers
  where
    blockers = Engine.noExtraHoistBlockers