{-
Tock: a compiler for parallel languages
Copyright (C) 2007  University of Kent

This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation, either version 2 of the License, or (at your
option) any later version.

This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License along
with this program.  If not, see <http://www.gnu.org/licenses/>.
-}

-- | Simplify types in the AST.
module SimplifyTypes (simplifyTypes) where

import Control.Monad.State
import Data.Generics

import qualified AST as A
import Pass
import Types

simplifyTypes :: A.Process -> PassM A.Process
simplifyTypes = runPasses passes
  where
    passes =
      [ ("Resolve types in AST", resolveNamedTypes)
      , ("Resolve types in state", rntState)
      ]

-- | Turn named data types into their underlying types.
resolveNamedTypes :: Data t => t -> PassM t
resolveNamedTypes = doGeneric `extM` doType
  where
    doGeneric :: Data t => t -> PassM t
    doGeneric = makeGeneric resolveNamedTypes

    doType :: A.Type -> PassM A.Type
    doType t@(A.UserDataType _) = underlyingType t
    doType t = doGeneric t

-- | Resolve named types in CompState.
rntState :: A.Process -> PassM A.Process
rntState p
    =  do st <- get
          st' <- resolveNamedTypes st
          put st'
          return p