{-  Copyright 2010 Dominique Devriese

    This file is part of the grammar-combinators library.

    The grammar-combinators library is free software: you can
    redistribute it and/or modify it under the terms of the GNU
    Lesser General Public License as published by the Free
    Software Foundation, either version 3 of the License, or (at
    your option) any later version.

    Foobar 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 Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General
    Public License along with Foobar. If not, see
    <http://www.gnu.org/licenses/>.
-}
{-# LANGUAGE EmptyDataDecls #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE TypeFamilies #-}

module Text.GrammarCombinators.Test.IndRec where


import Text.GrammarCombinators.Base
import Text.GrammarCombinators.Utils.PrintGrammar
import Text.GrammarCombinators.Parser.Parsec
import Text.GrammarCombinators.Parser.Packrat
import Text.GrammarCombinators.Transform.OptimizeGrammar
import Text.GrammarCombinators.Transform.FoldLoops
import Text.GrammarCombinators.Transform.UnfoldDead
import Text.GrammarCombinators.Utils.IsDead
import Text.GrammarCombinators.Utils.EnumerateGrammar
import Text.GrammarCombinators.Transform.UniformPaull
import Text.GrammarCombinators.Transform.LeftCorner
import Text.GrammarCombinators.Transform.FilterDies
import Text.GrammarCombinators.Utils.IsReachable


data A
data B

data ABDom ix where
  A :: ABDom A
  B :: ABDom B

instance MemoFam ABDom where
  data Memo ABDom r = ABM (r A) (r B)
  fromMemo (ABM v _) A = v
  fromMemo (ABM _ v) B = v
  toMemo f = ABM (f A) (f B)

instance EqFam ABDom where
  overrideIdx f A v A = v
  overrideIdx f B v B = v
  overrideIdx f _ _ idx = f idx
instance ShowFam ABDom where
  showIdx A = "A"
  showIdx B = "B"
instance FoldFam ABDom where
  foldFam f n = f A $ f B n
instance Domain ABDom

data PFAB r ix where
  A1F :: r B -> r A -> PFAB r A
  A3F :: PFAB r A
  B1F :: r A -> PFAB r B
  B2F :: PFAB r B

type instance PF ABDom = PFAB

grammar :: ContextFreeGrammar ABDom Char
grammar A =    A1F $>> ref B >>>* token 'a' >>> ref A
          |||  A3F $>>* token 'a'
grammar B =    B1F $>> ref A >>>* token 'b'
          ||| B2F $>>* token 'b'

proc :: Processor ABDom (K0 String)
proc A (A1F (K0 b) (K0 a)) = K0 $ b ++ "A" ++ a
proc A A3F = K0 ""
proc B (B1F (K0 a)) = K0 $ a ++ "B"
proc B B2F = K0 "B"

pg :: ProcessingContextFreeGrammar ABDom Char (K0 String)
pg = applyProcessor grammar proc