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curry-frontend-0.2.3: src/GenFlatCurry.hs

-------------------------------------------------------------------------------
-------------------------------------------------------------------------------
--
-- GenFlatCurry - Generates FlatCurry program terms and FlatCurry interfaces
--                (type 'FlatCurry.Prog')
--
-- November 2005,
-- Martin Engelke (men@informatik.uni-kiel.de)
--
module GenFlatCurry (genFlatCurry,
		     genFlatInterface) where


import Control.Monad.State
import Control.Monad
import Data.Maybe
import Data.List
import qualified Data.Map as Map


import Curry.Base.MessageMonad
import Curry.Base.Ident as Id

import qualified Curry.Syntax as CS

import Curry.ExtendedFlat.Type
import Curry.ExtendedFlat.TypeInference

import Base {-(ArityEnv, ArityInfo(..), ModuleEnv,  
	     TCEnv, TypeInfo(..), ValueEnv, ValueInfo(..),
	     lookupValue, qualLookupTC,
	     qualLookupArity, lookupArity,  internalError,
             qualLookupValue)-}

import qualified IL.Type as IL
import qualified IL.CurryToIL as IL

import TopEnv(topEnvMap)
import CurryEnv (CurryEnv)
import qualified CurryEnv
import ScopeEnv (ScopeEnv)
import qualified ScopeEnv
import Types
import CurryCompilerOpts
import PatchPrelude


import Debug.Trace
trace' _ x = x

-------------------------------------------------------------------------------

-- transforms intermediate language code (IL) to FlatCurry code
genFlatCurry :: Options -> CurryEnv -> ModuleEnv -> ValueEnv -> TCEnv 
		-> ArityEnv -> IL.Module -> (Prog, [WarnMsg])
genFlatCurry opts cEnv mEnv tyEnv tcEnv aEnv mod
   = (prog', messages)
 where (prog, messages) 
           = run opts cEnv mEnv tyEnv tcEnv aEnv False (visitModule mod)
       prog' = adjustTypeInfo $ patchPreludeFCY prog


-- transforms intermediate language code (IL) to FlatCurry interfaces
genFlatInterface :: Options -> CurryEnv -> ModuleEnv -> ValueEnv -> TCEnv
		 -> ArityEnv -> IL.Module -> (Prog, [WarnMsg])
genFlatInterface opts cEnv mEnv tyEnv tcEnv aEnv mod
   = (patchPreludeFCY intf, messages)
 where (intf, messages) 
	   = run opts cEnv mEnv tyEnv tcEnv aEnv True (visitModule mod)


-------------------------------------------------------------------------------
-------------------------------------------------------------------------------


-- The environment 'FlatEnv' is embedded in the monadic representation
-- 'FlatState' which allows the usage of 'do' expressions.

type FlatState a = State FlatEnv a

-- Data type for representing an environment which contains information needed
-- for generating FlatCurry code.
data FlatEnv = FlatEnv{ moduleIdE     :: ModuleIdent,
			  functionIdE   :: (QualIdent, [(Ident, IL.Type)]),
			  compilerOptsE :: Options,
			  moduleEnvE    :: ModuleEnv,
			  arityEnvE     :: ArityEnv,
			  typeEnvE      :: ValueEnv,     -- types of defined values
			  tConsEnvE     :: TCEnv,
			  publicEnvE    :: Map.Map Ident IdentExport,
			  fixitiesE     :: [CS.IDecl],
			  typeSynonymsE :: [CS.IDecl],
			  importsE      :: [CS.IDecl],
			  exportsE      :: [CS.Export],
			  interfaceE    :: [CS.IDecl],
			  varIndexE     :: Int,
			  varIdsE       :: ScopeEnv Ident VarIndex,
			  tvarIndexE    :: Int,
			  messagesE     :: [WarnMsg],
			  genInterfaceE :: Bool,
                          localTypes    :: Map.Map QualIdent IL.Type,
                          constrTypes   :: Map.Map QualIdent IL.Type
			}

data IdentExport = NotConstr       -- function, type-constructor
                 | OnlyConstr      -- constructor
                 | NotOnlyConstr   -- constructor, function, type-constructor




-- Runs a 'FlatState' action and returns the result
run :: Options -> CurryEnv -> ModuleEnv -> ValueEnv -> TCEnv -> ArityEnv 
    -> Bool -> FlatState a -> (a, [WarnMsg])
run opts cEnv mEnv tyEnv tcEnv aEnv genIntf f
   = (result, messagesE env)
 where
 (result, env) = runState f env0
 env0 = FlatEnv{ moduleIdE     = CurryEnv.moduleId cEnv,
		 functionIdE   = (qualify (mkIdent ""), []),
		 compilerOptsE = opts,
		 moduleEnvE    = mEnv,
		 arityEnvE     = aEnv,
		 typeEnvE      = tyEnv,
		 tConsEnvE     = tcEnv,
		 publicEnvE    = genPubEnv (CurryEnv.moduleId cEnv)
		                 (CurryEnv.interface cEnv),
		 fixitiesE     = CurryEnv.infixDecls cEnv,
		 typeSynonymsE = CurryEnv.typeSynonyms cEnv,
		 importsE      = CurryEnv.imports cEnv,
		 exportsE      = CurryEnv.exports cEnv,
		 interfaceE    = CurryEnv.interface cEnv,
		 varIndexE     = 0,
		 varIdsE       = ScopeEnv.new,
		 tvarIndexE    =0,
		 messagesE      = [],
		 genInterfaceE = genIntf,
                 localTypes    = Map.empty,
                 constrTypes   = Map.fromList (getConstrTypes tcEnv)
	       }

getConstrTypes :: TCEnv -> [(QualIdent, IL.Type)]
getConstrTypes tcEnv = trace' (show tinfos) tinfos
    where tcList = Map.toList $ topEnvMap tcEnv
          tinfos = [ foo tqid conid argtypes targnum
                   | (_, (_, DataType tqid targnum dts):_) <- tcList
                   , Just (Data conid _ argtypes) <- dts]
          foo tqid conid argtypes targnum
              = let conname = QualIdent (qualidMod tqid) conid
                    resulttype = IL.TypeConstructor tqid (map IL.TypeVariable [0..targnum-1])
                    contype = foldr IL.TypeArrow resulttype (map ttrans argtypes)
                in (conname, contype)
              

--
visitModule :: IL.Module -> FlatState Prog
visitModule (IL.Module mid imps decls) = do
  -- insert local decls into localDecls
  let ts = [ (qn, t) | IL.FunctionDecl qn _ t _ <- decls ]
  modify (\ s -> s {localTypes = Map.fromList ts})
  whenFlatCurry
       (do ops     <- genOpDecls
           datas   <- mapM visitDataDecl (filter isDataDecl decls)
	   types   <- genTypeSynonyms
	   records <- genRecordTypes
	   funcs   <- mapM visitFuncDecl (filter isFuncDecl decls)
	   mod     <- visitModuleIdent mid
	   imps'   <- imports
	   is      <- mapM visitModuleIdent 
	                   (nub (imps ++ (map (\ (CS.IImportDecl _ mid) 
					       -> mid) imps')))
           return (Prog mod is (records ++ types ++ datas) funcs ops))
       (do ops     <- genOpDecls
	   ds      <- filterM isPublicDataDecl decls
	   datas   <- mapM visitDataDecl ds
	   types   <- genTypeSynonyms
	   records <- genRecordTypes
	   fs      <- filterM isPublicFuncDecl decls
	   funcs   <- mapM visitFuncDecl fs
	   expimps <- getExportedImports
	   itypes  <- mapM visitTypeIDecl (filter isTypeIDecl expimps)
	   ifuncs  <- mapM visitFuncIDecl (filter isFuncIDecl expimps)
	   iops    <- mapM visitOpIDecl (filter isOpIDecl expimps)
	   mod     <- visitModuleIdent mid
	   imps'   <- imports
	   is      <- mapM visitModuleIdent 
	                   (nub (imps ++ (map (\ (CS.IImportDecl _ mid) 
					       -> mid) imps')))
	   return (Prog mod 
		        is 
		        (itypes ++ records ++ types ++ datas)
		        (ifuncs ++ funcs)
		        (iops ++ ops)))

--
visitDataDecl :: IL.Decl -> FlatState TypeDecl
visitDataDecl (IL.DataDecl qident arity constrs)
   = do cdecls <- mapM visitConstrDecl constrs
	qname  <- visitQualIdent qident
	vis    <- getVisibility False qident
	return (Type qname vis [0 .. (arity - 1)] (concat cdecls))
visitDataDecl _ = internalError "GenFlatCurry: no data declaration"

--
visitConstrDecl :: IL.ConstrDecl [IL.Type] -> FlatState [ConsDecl]
visitConstrDecl (IL.ConstrDecl qident types)
   = do texprs <- mapM visitType types
	qname  <- visitQualIdent qident
	vis    <- getVisibility True qident
        genFint <- genInterface
        if genFint && vis == Private 
          then return []
          else return [Cons qname (length types) vis texprs]

--
visitType :: IL.Type -> FlatState TypeExpr
visitType (IL.TypeConstructor qident types)
   = do texprs <- mapM visitType types
	qname  <- visitQualTypeIdent qident
	if (qualName qident) == "Identity"
	   then return (head texprs)
	   else return (TCons qname texprs)
visitType (IL.TypeVariable index)
   = return (TVar (abs index))
visitType (IL.TypeArrow type1 type2)
   = do texpr1 <- visitType type1
	texpr2 <- visitType type2
	return (FuncType texpr1 texpr2)

--
visitFuncDecl :: IL.Decl -> FlatState FuncDecl
visitFuncDecl (IL.FunctionDecl qident params typeexpr expression)
   = let argtypes = splitoffArgTypes typeexpr params 
     in do setFunctionId (qident, argtypes)
           qname <- visitQualIdent qident
           whenFlatCurry (do is    <- mapM newVarIndex params
	                     texpr <- visitType typeexpr
	                     expr  <- visitExpression expression
	                     vis   <- getVisibility False qident
	                     clearVarIndices
	                     return (Func qname (length params) vis texpr (Rule is expr)))
                         (do texpr <- visitType typeexpr
	                     clearVarIndices
	                     return (Func qname (length params) Public texpr (Rule [] (Var $ mkIdx 0))))
visitFuncDecl (IL.ExternalDecl qident _ name typeexpr)
   = do setFunctionId (qident, [])
	texpr <- visitType typeexpr
	qname <- visitQualIdent qident
	vis   <- getVisibility False qident
	xname <- visitExternalName name
	return (Func qname (typeArity typeexpr) vis texpr (External xname))
visitFuncDecl (IL.NewtypeDecl _ _ _)
   = do mid <- moduleId 
	error ("\"" ++ Id.moduleName mid 
	       ++ "\": newtype declarations are not supported")
visitFuncDecl _ = internalError "GenFlatCurry: no function declaration"

--
visitExpression :: IL.Expression -> FlatState Expr
visitExpression (IL.Literal literal)
   = liftM Lit (visitLiteral literal)
visitExpression (IL.Variable ident)
   = liftM Var (lookupVarIndex ident)
visitExpression (IL.Function qident _)
   = do arity_ <- lookupIdArity qident
        qname <- visitQualIdent qident
	maybe (internalError (funcArity qname))
	      (\arity -> genFuncCall qname arity [])
	      arity_
visitExpression (IL.Constructor qident arity)
   = do arity_ <- lookupIdArity qident
        qname <- visitQualIdent qident
	maybe (internalError (consArity qident))
	      (\arity -> genConsCall qname arity [])
	      arity_
visitExpression (IL.Apply e1 e2)
   = genFlatApplication e1 e2
visitExpression (IL.Case r evalannot expression alts)
   = do ea       <- visitEval evalannot
	expr     <- visitExpression expression
	branches <- mapM visitAlt alts
	return (Case r ea expr branches)
visitExpression (IL.Or expression1 expression2)
   = do expr1 <- visitExpression expression1
	expr2 <- visitExpression expression2
	checkOverlapping expr1 expr2
	return (Or expr1 expr2)
visitExpression (IL.Exist ident expression)
   = do index <- newVarIndex ident
	expr  <- visitExpression expression
	case expr of
	  Free is expr' -> return (Free (index:is) expr')
	  _             -> return (Free [index] expr)
visitExpression (IL.Let binding expression)
   = do beginScope
	newVarIndex (bindingIdent binding)
        bind <- visitBinding binding
	expr <- visitExpression expression
        -- is it correct that there is no endScope? (hsi)
        return (Let [bind] expr)
visitExpression (IL.Letrec bindings expression)
   = do beginScope
	mapM_ (newVarIndex . bindingIdent) bindings
	binds <- mapM visitBinding bindings
	expr  <- visitExpression expression
	endScope
	return (Let binds expr)


--
visitLiteral :: IL.Literal -> FlatState Literal
visitLiteral (IL.Char rs c)  = return (Charc rs c)
visitLiteral (IL.Int rs i)   = return (Intc rs i)
visitLiteral (IL.Float rs f) = return (Floatc rs f)

--
visitAlt :: IL.Alt -> FlatState BranchExpr
visitAlt (IL.Alt cterm expression)
   = do patt <- visitConstrTerm cterm
	expr <- visitExpression expression
	return (Branch patt expr)

--
visitConstrTerm :: IL.ConstrTerm -> FlatState Pattern
visitConstrTerm (IL.LiteralPattern literal)
   = do lit <- visitLiteral literal
	return (LPattern lit)
visitConstrTerm (IL.ConstructorPattern qident args)
   = do is    <- mapM newVarIndex args
	qname <- visitQualIdent qident
	return (Pattern qname is)
visitConstrTerm (IL.VariablePattern ident)
   = do mid <- moduleId
	error ("\"" ++ Id.moduleName mid 
	       ++ "\": variable patterns are not supported")

--
visitEval :: IL.Eval -> FlatState CaseType
visitEval IL.Rigid = return Rigid
visitEval IL.Flex  = return Flex

--
visitBinding :: IL.Binding -> FlatState (VarIndex, Expr)
visitBinding (IL.Binding ident expression)
   = do index <- lookupVarIndex ident
	expr  <- visitExpression expression
	return (index, expr)


-------------------------------------------------------------------------------

--
visitFuncIDecl :: CS.IDecl -> FlatState FuncDecl
visitFuncIDecl (CS.IFunctionDecl _ qident arity typeexpr)
   = do texpr <- visitType (fst (cs2ilType [] typeexpr))
	qname <- visitQualIdent qident
	return (Func qname arity Public texpr (Rule [] (Var $ mkIdx 0)))
visitFuncIDecl _ = internalError "GenFlatCurry: no function interface"

--
visitTypeIDecl :: CS.IDecl -> FlatState TypeDecl
visitTypeIDecl (CS.IDataDecl _ qident params constrs_)
   = do let mid = fromMaybe (internalError "GenFlatCurry: no module name")
		            (qualidMod qident)
	    is  = [0 .. length params - 1]
	cdecls <- mapM (visitConstrIDecl mid (zip params is)) 
		       (catMaybes constrs_)
	qname  <- visitQualIdent qident
	return (Type qname Public is cdecls)
visitTypeIDecl (CS.ITypeDecl _ qident params typeexpr)
   = do let is = [0 .. (length params) - 1]
	texpr <- visitType (fst (cs2ilType (zip params is) typeexpr))
	qname <- visitQualIdent qident
	return (TypeSyn qname Public is texpr)
visitTypeIDecl _ = internalError "GenFlatCurry: no type interface"

--
visitConstrIDecl :: ModuleIdent -> [(Ident, Int)] -> CS.ConstrDecl 
		    -> FlatState ConsDecl
visitConstrIDecl mid tis (CS.ConstrDecl _ _ ident typeexprs)
   = do texprs <- mapM (visitType . (fst . cs2ilType tis)) typeexprs
	qname  <- visitQualIdent (qualifyWith mid ident)
	return (Cons qname (length typeexprs) Public texprs)
visitConstrIDecl mid tis (CS.ConOpDecl pos ids type1 ident type2)
   = visitConstrIDecl mid tis (CS.ConstrDecl pos ids ident [type1,type2])

--
visitOpIDecl :: CS.IDecl -> FlatState OpDecl
visitOpIDecl (CS.IInfixDecl _ fixity prec qident)
   = do let fix = case fixity of
	            CS.InfixL -> InfixlOp
		    CS.InfixR -> InfixrOp
		    _         -> InfixOp
        qname <- visitQualIdent qident
	return (Op qname fix prec)


-------------------------------------------------------------------------------

--
visitModuleIdent :: ModuleIdent -> FlatState String
visitModuleIdent = return . Id.moduleName

--
visitQualIdent :: QualIdent -> FlatState QName
visitQualIdent qident
   = do mid <- moduleId
	let (mmod, ident) = (qualidMod qident, qualidId qident)
	    mod | elem ident [listId, consId, nilId, unitId] || isTupleId ident
		  = Id.moduleName preludeMIdent
		| otherwise
		  = maybe (Id.moduleName mid) Id.moduleName mmod
        ftype <- lookupIdType qident
	return (QName Nothing ftype mod $ name ident)

-- This variant of visitQualIdent does not look up the type of the identifier,
-- which is wise when the identifier is bound to a type, because looking up
-- the type of a type via lookupIdType will get stuck in an endless loop. (hsi)
visitQualTypeIdent :: QualIdent -> FlatState QName
visitQualTypeIdent qident
   = do mid <- moduleId
	let (mmod, ident) = (qualidMod qident, qualidId qident)
	    mod | elem ident [listId, consId, nilId, unitId] || isTupleId ident
		  = Id.moduleName preludeMIdent
		| otherwise
		  = maybe (Id.moduleName mid) Id.moduleName mmod
	return (QName Nothing Nothing mod $ name ident)

--
visitExternalName :: String -> FlatState String
visitExternalName name 
   = moduleId >>= \mid -> return (Id.moduleName mid ++ "." ++ name)


-------------------------------------------------------------------------------
-------------------------------------------------------------------------------

--
getVisibility :: Bool -> QualIdent -> FlatState Visibility
getVisibility isConstr qident
   = do public <- isPublic isConstr qident
	if public then return Public else return Private


--
getExportedImports :: FlatState [CS.IDecl]
getExportedImports
   = do mid  <- moduleId
	exps <- exports
	genExportedIDecls (Map.toList (getExpImports mid Map.empty exps))

--
getExpImports :: ModuleIdent -> Map.Map ModuleIdent [CS.Export] -> [CS.Export]
		 -> Map.Map ModuleIdent [CS.Export]
getExpImports mident expenv [] = expenv
getExpImports mident expenv ((CS.Export qident):exps)
   = getExpImports mident 
	           (bindExpImport mident qident (CS.Export qident) expenv) 
		   exps
getExpImports mident expenv ((CS.ExportTypeWith qident idents):exps)
   = getExpImports mident 
		   (bindExpImport mident 
		                  qident 
		                  (CS.ExportTypeWith qident idents) 
		                  expenv)
		   exps
getExpImports mident expenv ((CS.ExportTypeAll qident):exps)
   = getExpImports mident 
	 	   (bindExpImport mident qident (CS.ExportTypeAll qident) expenv) 
		   exps
getExpImports mident expenv ((CS.ExportModule mident'):exps)
   = getExpImports mident (Map.insert mident' [] expenv) exps

--
bindExpImport :: ModuleIdent -> QualIdent -> CS.Export 
	         -> Map.Map ModuleIdent [CS.Export] -> Map.Map ModuleIdent [CS.Export]
bindExpImport mident qident export expenv
   | isJust (localIdent mident qident)
     = expenv
   | otherwise
     = let (Just mod) = qualidMod qident
       in  maybe (Map.insert mod [export] expenv)
	         (\es -> Map.insert mod (export:es) expenv) 
		 (Map.lookup mod expenv)

--
genExportedIDecls :: [(ModuleIdent,[CS.Export])] -> FlatState [CS.IDecl]
genExportedIDecls mes = genExpIDecls [] mes

--
genExpIDecls :: [CS.IDecl] -> [(ModuleIdent,[CS.Export])] -> FlatState [CS.IDecl]
genExpIDecls idecls [] = return idecls
genExpIDecls idecls ((mid,exps):mes)
   = do intf_ <- lookupModuleIntf mid
	let idecls' = maybe idecls (p_genExpIDecls mid idecls exps) intf_
	genExpIDecls idecls' mes
 where
   p_genExpIDecls mid idecls exps intf
      | null exps = (map (qualifyIDecl mid) intf) ++ idecls
      | otherwise = (filter (isExportedIDecl exps) 
		            (map (qualifyIDecl mid) intf))
		    ++ idecls

-- 
isExportedIDecl :: [CS.Export] -> CS.IDecl -> Bool
isExportedIDecl exports (CS.IInfixDecl _ _ _ qident)
   = isExportedQualIdent qident exports
isExportedIDecl exports (CS.IDataDecl _ qident _ _)
   = isExportedQualIdent qident exports
isExportedIDecl exports (CS.ITypeDecl _ qident _ _)
   = isExportedQualIdent qident exports
isExportedIDecl exports (CS.IFunctionDecl _ qident _ _)
   = isExportedQualIdent qident exports
isExportedIDecl exports _
   = False

--
isExportedQualIdent :: QualIdent -> [CS.Export] -> Bool
isExportedQualIdent qident [] = False
isExportedQualIdent qident ((CS.Export qident'):exps)
   = qident == qident' || isExportedQualIdent qident exps
isExportedQualIdent qident ((CS.ExportTypeWith qident' idents):exps)
   = qident == qident' || isExportedQualIdent qident exps
isExportedQualIdent qident ((CS.ExportTypeAll qident'):exps)
   = qident == qident' || isExportedQualIdent qident exps
isExportedQualIdent qident ((CS.ExportModule _):exps)
   = isExportedQualIdent qident exps

--
qualifyIDecl :: ModuleIdent -> CS.IDecl -> CS.IDecl
qualifyIDecl mident (CS.IInfixDecl pos fix prec qident)
   = (CS.IInfixDecl pos fix prec (qualQualify mident qident))
qualifyIDecl mident (CS.IDataDecl pos qident idents cdecls)
   = (CS.IDataDecl pos (qualQualify mident qident) idents cdecls)
qualifyIDecl mident (CS.INewtypeDecl pos qident idents ncdecl)
   = (CS.INewtypeDecl pos (qualQualify mident qident) idents ncdecl)
qualifyIDecl mident (CS.ITypeDecl pos qident idents texpr)
   = (CS.ITypeDecl pos (qualQualify mident qident) idents texpr)
qualifyIDecl mident (CS.IFunctionDecl pos qident arity texpr)
   = (CS.IFunctionDecl pos (qualQualify mident qident) arity texpr)
qualifyIDecl _ idecl = idecl


--
typeArity :: IL.Type -> Int
typeArity (IL.TypeArrow _ t)       = 1 + (typeArity t)
typeArity (IL.TypeConstructor _ _) = 0
typeArity (IL.TypeVariable _)      = 0


-------------------------------------------------------------------------------

--
genFlatApplication :: IL.Expression -> IL.Expression -> FlatState Expr
genFlatApplication e1 e2
   = genFlatApplic [e2] e1
 where
   genFlatApplic args expression 
      = case expression of
	  (IL.Apply expr1 expr2)    
	      -> genFlatApplic (expr2:args) expr1
	  (IL.Function qident _)
	      -> do arity_ <- lookupIdArity qident
                    qname <- visitQualIdent qident
		    maybe (internalError (funcArity qident))
			  (\arity -> genFuncCall qname arity args)
			  arity_
	  (IL.Constructor qident _)
	      -> do arity_ <- lookupIdArity qident
                    qname <- visitQualIdent qident
		    maybe (internalError (consArity qident))
			  (\arity -> genConsCall qname arity args)
			  arity_
	  _   -> do expr <- visitExpression expression
		    genApplicComb expr args

--
genFuncCall :: QName -> Int -> [IL.Expression] -> FlatState Expr
genFuncCall qname arity args
   | arity > cnt 
     = genComb qname args (FuncPartCall (arity - cnt))
   | arity < cnt 
     = do let (funcargs, applicargs) = splitAt arity args
	  funccall <- genComb qname funcargs FuncCall
	  genApplicComb funccall applicargs
   | otherwise   
     = genComb qname args FuncCall
 where cnt = length args

--
genConsCall :: QName -> Int -> [IL.Expression] -> FlatState Expr
genConsCall qname arity args
   | arity > cnt 
     = genComb qname args (ConsPartCall (arity - cnt))
   | arity < cnt
     = do let (funcargs, applicargs) = splitAt arity args
	  conscall <- genComb qname funcargs ConsCall
	  genApplicComb conscall applicargs
   | otherwise 
     = genComb qname args ConsCall 
 where cnt = length args

--
genComb :: QName -> [IL.Expression] -> CombType -> FlatState Expr
genComb qname args combtype
   = do exprs <- mapM visitExpression args
	return (Comb combtype qname exprs)
	 
--
genApplicComb :: Expr -> [IL.Expression] -> FlatState Expr
genApplicComb expr [] = return expr
genApplicComb expr (e1:es)
   = do expr1 <- visitExpression e1
	qname <- visitQualIdent qidApply
	genApplicComb (Comb FuncCall qname [expr, expr1]) es
 where
 qidApply = qualifyWith preludeMIdent (mkIdent "apply")


--
genOpDecls :: FlatState [OpDecl]
genOpDecls = fixities >>= mapM genOpDecl

--
genOpDecl :: CS.IDecl -> FlatState OpDecl
genOpDecl (CS.IInfixDecl _ fixity prec qident)
   = do qname <- visitQualIdent qident
	return (Op qname (p_genOpFixity fixity) prec)
 where
   p_genOpFixity CS.InfixL = InfixlOp
   p_genOpFixity CS.InfixR = InfixrOp
   p_genOpFixity CS.Infix  = InfixOp
genOpDecl _ = internalError "GenFlatCurry: no infix interface"


-- The intermediate language (IL) does not represent type synonyms
-- (and also no record declarations). For this reason an interface
-- representation of all type synonyms is generated (see "CurryEnv")
-- from the abstract syntax representation of the Curry program.
-- The function 'typeSynonyms' returns this list of type synonyms.
genTypeSynonyms ::  FlatState [TypeDecl]
genTypeSynonyms = typeSynonyms >>= mapM genTypeSynonym

--
genTypeSynonym :: CS.IDecl -> FlatState TypeDecl
genTypeSynonym (CS.ITypeDecl _ qident params typeexpr)
   = do let is = [0 .. (length params) - 1]
        tyEnv <- gets typeEnvE
        tcEnv <- gets tConsEnvE
	let typeexpr' = elimRecordTypes tyEnv tcEnv typeexpr
	texpr <- visitType (fst (cs2ilType (zip params is) typeexpr'))
	qname <- visitQualIdent qident
	vis   <- getVisibility False qident
	return (TypeSyn qname vis is texpr)
genTypeSynonym _ = internalError "GenFlatCurry: no type synonym interface"


-- In order to provide an interface for record declarations, 'genRecordTypes'
-- generates dummy data declarations representing records together
-- with their typed labels. For the record declaration
--
--      type Rec = {l_1 :: t_1,..., l_n :: t_n}
--
-- the following data declaration will be generated:
--
--      data Rec' = l_1' t_1 | ... | l_n' :: t_n
--
-- Rec' and l_i' are unique idenfifiers which encode the original names
-- Rec and l_i.
-- When reading an interface file containing such declarations, it is
-- now possible to reconstruct the original record declaration. Since
-- usual FlatCurry code is used, these declaration should not have any
-- effects on the behaviour of the Curry program. But to ensure correctness,
-- these dummies should be generated for the interface file as well as for
-- the corresponding FlatCurry file.
genRecordTypes :: FlatState [TypeDecl]
genRecordTypes = records >>= mapM genRecordType

--
genRecordType :: CS.IDecl -> FlatState TypeDecl
genRecordType (CS.ITypeDecl _ qident params (CS.RecordType fields _))
   = do let is = [0 .. (length params) - 1]
	    (mod,ident) = (qualidMod qident, qualidId qident)
	qname <- visitQualIdent ((maybe qualify qualifyWith mod) 
				 (recordExtId ident))
	labels <- mapM (genRecordLabel mod (zip params is)) fields
	return (Type qname Public is labels)

--
genRecordLabel :: Maybe ModuleIdent -> [(Ident,Int)] -> ([Ident],CS.TypeExpr) 
	       -> FlatState ConsDecl
genRecordLabel mod vis ([ident],typeexpr)
   = do tyEnv <- gets typeEnvE
        tcEnv <- gets tConsEnvE
	let typeexpr' = elimRecordTypes tyEnv tcEnv typeexpr
        texpr <- visitType (fst (cs2ilType vis typeexpr'))
	qname <- visitQualIdent ((maybe qualify qualifyWith mod) 
				 (labelExtId ident))
	return (Cons qname 1 Public [texpr])


-------------------------------------------------------------------------------

-- FlatCurry provides no possibility of representing record types like
-- {l_1::t_1, l_2::t_2, ..., l_n::t_n}. So they have to be transformed to
-- to the corresponding type constructors which are defined in the record 
-- declarations. 
-- Unlike data declarations or function type annotations, type synonyms and
-- record declarations are not generated from the intermediate language.
-- So the transformation has only to be performed in these cases.
elimRecordTypes :: ValueEnv -> TCEnv -> CS.TypeExpr -> CS.TypeExpr
elimRecordTypes tyEnv tcEnv (CS.ConstructorType qid typeexprs)
   = CS.ConstructorType qid (map (elimRecordTypes tyEnv tcEnv) typeexprs)
elimRecordTypes tyEnv tcEnv (CS.VariableType id)
   = CS.VariableType id
elimRecordTypes tyEnv tcEnv (CS.TupleType typeexprs)
   = CS.TupleType (map (elimRecordTypes tyEnv tcEnv) typeexprs)
elimRecordTypes tyEnv tcEnv (CS.ListType typeexpr)
   = CS.ListType (elimRecordTypes tyEnv tcEnv typeexpr)
elimRecordTypes tyEnv tcEnv (CS.ArrowType typeexpr1 typeexpr2)
   = CS.ArrowType (elimRecordTypes tyEnv tcEnv typeexpr1)
                  (elimRecordTypes tyEnv tcEnv typeexpr2)
elimRecordTypes tyEnv tcEnv (CS.RecordType fss _)
   = let fs = flattenRecordTypeFields fss
     in  case (lookupValue (fst (head fs)) tyEnv) of
  	   [Label _ record _] ->
	     case (qualLookupTC record tcEnv) of
	       [AliasType _ n (TypeRecord fs' _)] ->
	         let ms = foldl (matchTypeVars fs) Map.empty fs'
		     types = map (\i -> maybe 
			 	          (CS.VariableType 
					     (mkIdent ("#tvar" ++ show i)))
				          (elimRecordTypes tyEnv tcEnv)
				          (Map.lookup i ms))
			         [0 .. n-1]
	         in  CS.ConstructorType record types
	       _ -> internalError ("GenFlatCurry.elimRecordTypes: "
		 		   ++ "no record type")
	   _ -> internalError ("GenFlatCurry.elimRecordTypes: "
			       ++ "no label")

matchTypeVars :: [(Ident,CS.TypeExpr)] -> Map.Map Int CS.TypeExpr
	      -> (Ident, Type) -> Map.Map Int CS.TypeExpr
matchTypeVars fs ms (l,ty)
   = maybe ms (match ms ty) (lookup l fs)
  where
  match ms (TypeVariable i) typeexpr = Map.insert i typeexpr ms
  match ms (TypeConstructor _ tys) (CS.ConstructorType _ typeexprs)
     = matchList ms tys typeexprs
  match ms (TypeConstructor _ tys) (CS.ListType typeexpr)
     = matchList ms tys [typeexpr]
  match ms (TypeConstructor _ tys) (CS.TupleType typeexprs)
     = matchList ms tys typeexprs
  match ms (TypeArrow ty1 ty2) (CS.ArrowType typeexpr1 typeexpr2)
     = matchList ms [ty1,ty2] [typeexpr1,typeexpr2]
  match ms (TypeRecord fs' _) (CS.RecordType fss _)
     = foldl (matchTypeVars (flattenRecordTypeFields fss)) ms fs'
  match ms ty typeexpr
     = internalError ("GenFlatCurry.matchTypeVars: "
		      ++ show ty ++ "\n" ++ show typeexpr)

  matchList ms tys
     = foldl (\ms' (ty,typeexpr) -> match ms' ty typeexpr) ms . zip tys


flattenRecordTypeFields :: [([Ident],CS.TypeExpr)] -> [(Ident,CS.TypeExpr)]
flattenRecordTypeFields
   = concatMap (\ (labels, typeexpr)
		-> map (\label -> (label,typeexpr)) labels)

-------------------------------------------------------------------------------

--
checkOverlapping :: Expr -> Expr -> FlatState ()
checkOverlapping expr1 expr2
   = do opts <- compilerOpts
	unless (noOverlapWarn opts)
	       (checkOverlap expr1 expr2)
 where
 checkOverlap (Case _ _ _ _) _ 
    = do qid <- functionId
	 genWarning (overlappingRules qid)
 checkOverlap _ (Case _ _ _ _)
    = do qid <- functionId
	 genWarning (overlappingRules qid)
 checkOverlap _ _ = return ()


-------------------------------------------------------------------------------

-- 
cs2ilType :: [(Ident,Int)] -> CS.TypeExpr -> (IL.Type, [(Ident,Int)])
cs2ilType ids (CS.ConstructorType qident typeexprs)
   = let (ilTypeexprs, ids') = emap cs2ilType ids typeexprs
     in  (IL.TypeConstructor qident ilTypeexprs, ids')
cs2ilType ids (CS.VariableType ident)
   = let mid        = lookup ident ids
	 nid        | null ids  = 0
		    | otherwise = 1 + snd (head ids)
	 (id, ids') | isJust mid = (fromJust mid, ids)
		    | otherwise  = (nid, (ident, nid):ids)
     in  (IL.TypeVariable id, ids')
cs2ilType ids (CS.ArrowType type1 type2)
   = let (ilType1, ids')  = cs2ilType ids type1
	 (ilType2, ids'') = cs2ilType ids' type2
     in  (IL.TypeArrow ilType1 ilType2, ids'')
cs2ilType ids (CS.ListType typeexpr)
   = let (ilTypeexpr, ids') = cs2ilType ids typeexpr
     in  (IL.TypeConstructor (qualify listId) [ilTypeexpr], ids')
cs2ilType ids (CS.TupleType typeexprs)
   = case typeexprs of
       []  -> (IL.TypeConstructor qUnitId [], ids)
       [t] -> cs2ilType ids t
       _   -> let (ilTypeexprs, ids') = emap cs2ilType ids typeexprs
		  tuplen = length ilTypeexprs
	      in  (IL.TypeConstructor (qTupleId tuplen) ilTypeexprs,
		   ids')
cs2ilType _ typeexpr = internalError ("cs2ilType: " ++ show typeexpr)


-------------------------------------------------------------------------------
-- Messages for internal errors and warnings

funcArity qid = "GenFlatCurry: missing arity for function \"" 
		++ show qid ++ "\""

consArity qid = "GenFlatCurry: missing arity for constructor \""
		++ show qid ++ "\""

missingVarIndex id = "GenFlatCurry: missing index for \"" ++ show id ++ "\""


overlappingRules qid =  "function \""
		        ++ qualName qid 
		        ++ "\" is non-deterministic due to non-trivial "
		        ++ "overlapping rules"


-------------------------------------------------------------------------------
-------------------------------------------------------------------------------

--
isDataDecl :: IL.Decl -> Bool
isDataDecl (IL.DataDecl _ _ _) = True
isDataDecl _                = False

--
isFuncDecl :: IL.Decl -> Bool
isFuncDecl (IL.FunctionDecl _ _ _ _) = True
isFuncDecl (IL.ExternalDecl _ _ _ _) = True
isFuncDecl _                         = False

--
isPublicDataDecl :: IL.Decl -> FlatState Bool
isPublicDataDecl (IL.DataDecl qident _ _ ) = isPublic False qident
isPublicDataDecl _                         = return False

--
isPublicFuncDecl :: IL.Decl -> FlatState Bool
isPublicFuncDecl (IL.FunctionDecl qident _ _ _) = isPublic False qident
isPublicFuncDecl (IL.ExternalDecl qident _ _ _) = isPublic False qident
isPublicFuncDecl _                              = return False

--
isTypeIDecl :: CS.IDecl -> Bool
isTypeIDecl (CS.IDataDecl _ _ _ _) = True
isTypeIDecl (CS.ITypeDecl _ _ _ _) = True
isTypeIDecl _                      = False

--
isRecordIDecl :: CS.IDecl -> Bool
isRecordIDecl (CS.ITypeDecl _ _ _ (CS.RecordType (_:_) _)) = True
isRecordIDecl _                                            = False

--
isFuncIDecl :: CS.IDecl -> Bool
isFuncIDecl (CS.IFunctionDecl _ _ _ _) = True
isFuncIDecl _                          = False

--
isOpIDecl :: CS.IDecl -> Bool
isOpIDecl (CS.IInfixDecl _ _ _ _) = True
isOpIDecl _                       = False 


--
bindingIdent :: IL.Binding -> Ident
bindingIdent (IL.Binding ident _) = ident

-------------------------------------------------------------------------------
-------------------------------------------------------------------------------

emap :: (e -> a -> (b,e)) -> e -> [a] -> ([b], e)
emap _ env []     = ([], env)
emap f env (x:xs) = let (x',env')    = f env x
			(xs', env'') = emap f env' xs
		    in  ((x':xs'), env'')

-------------------------------------------------------------------------------
-------------------------------------------------------------------------------

--
moduleId :: FlatState ModuleIdent
moduleId = gets moduleIdE

--
functionId :: FlatState QualIdent
functionId = gets (fst . functionIdE)

--
setFunctionId :: (QualIdent, [(Ident, IL.Type)]) -> FlatState ()
setFunctionId qid = modify (\env -> env{ functionIdE = qid })

--
compilerOpts :: FlatState Options
compilerOpts = gets compilerOptsE

--
exports :: FlatState [CS.Export]
exports = gets exportsE

--
imports :: FlatState [CS.IDecl]
imports = gets importsE

--
records :: FlatState [CS.IDecl]
records = gets (filter isRecordIDecl . interfaceE)

--
fixities :: FlatState [CS.IDecl]
fixities = gets fixitiesE

--
typeSynonyms :: FlatState [CS.IDecl]
typeSynonyms = gets typeSynonymsE

--
isPublic :: Bool -> QualIdent -> FlatState Bool
isPublic isConstr qid = gets (\env -> maybe False isP
                                      (Map.lookup (unqualify qid) 
                                       (publicEnvE env)))
  where
    isP NotConstr = not isConstr
    isP OnlyConstr = isConstr
    isP NotOnlyConstr = True

--
lookupModuleIntf :: ModuleIdent -> FlatState (Maybe [CS.IDecl])
lookupModuleIntf mid
   = gets (Map.lookup mid . moduleEnvE)

--
lookupIdArity :: QualIdent -> FlatState (Maybe Int)
lookupIdArity qid
   = gets (lookupA qid . arityEnvE)
 where
 lookupA qid aEnv = case (qualLookupArity qid aEnv) of
		      [ArityInfo _ a]
		         -> Just a
		      [] -> case (lookupArity (unqualify qid) aEnv) of
			      [ArityInfo _ a] -> Just a
			      _               -> Nothing
		      _  -> Nothing



getTypeOf :: Ident -> FlatState (Maybe TypeExpr)
getTypeOf ident = do
    valEnv <- gets typeEnvE 
    case lookupValue ident valEnv of 
      Value _ (ForAll _ t) : _ 
          -> do t <- visitType (ttrans t)
                trace' ("getTypeOf(" ++ show ident ++ ") = " ++ show t)$
                       return (Just t)
      DataConstructor _ (ForAllExist _ _ t):_ 
          -> do t <- visitType (ttrans t)
                trace' ("getTypeOfDataCon(" ++ show ident ++ ") = " ++ show t)$
                       return (Just t)
      _   -> do (_,ats) <- gets functionIdE
                case lookup ident ats of
                  Just t -> liftM Just (visitType t)
                  Nothing -> trace' ("lookupValue did not return a value for index " ++ show ident)
                             (return Nothing)
ttrans :: Type -> IL.Type 
ttrans (TypeConstructor i ts)
    = IL.TypeConstructor i (map ttrans ts)
ttrans (TypeVariable v)
    = IL.TypeVariable v
ttrans (TypeConstrained [] v)
    = IL.TypeVariable v
ttrans (TypeConstrained (v:_) i)
    = ttrans v
ttrans (TypeArrow f x) = IL.TypeArrow (ttrans f) (ttrans x)
ttrans s@(TypeSkolem _) = error $ "in ttrans: " ++ show s
ttrans s@(TypeRecord _ _) = error $ "in ttrans: " ++ show s



-- Constructor (:) receives special treatment throughout the
-- whole implementation. We won't depart from that for mere
-- aesthetic reasons. (hsi)
lookupIdType :: QualIdent -> FlatState (Maybe TypeExpr)
lookupIdType (QualIdent Nothing (Ident _ ":" _))
    = return (Just (FuncType (TVar 0) (FuncType (l0) (l0))))
      where l0 = TCons (mkQName ("Prelude", "[]")) [TVar 0]
lookupIdType qid
   = do aEnv <- gets typeEnvE
        lt <- gets localTypes
        ct <- gets constrTypes
        case Map.lookup qid lt `mplus` Map.lookup qid ct of
          Just t -> trace' ("lookupIdType local " ++ show (qid, t)) $ liftM Just (visitType t)  -- local name or constructor
          Nothing -> case [ t | Value _ (ForAll _ t) <- qualLookupValue qid aEnv ] of 
                       t : _ -> liftM Just (visitType (IL.translType t))  -- imported name
                       []    -> case qualidMod qid of
                                  Nothing -> trace' ("no type for "  ++ show qid) $ return Nothing  -- no known type
                                  Just _ -> lookupIdType qid {qualidMod = Nothing}
-- 

-- Generates a new index for a variable
newVarIndex :: Ident -> FlatState VarIndex
newVarIndex ident
   = do idx0 <- gets varIndexE
        ty <- getTypeOf ident
        let idx = idx0 + 1
            vid = VarIndex ty idx
        vids <- gets varIdsE
        modify (\env -> env{ varIndexE = idx,
			     varIdsE   = ScopeEnv.insert ident vid vids
			   })
        return vid

--
lookupVarIndex :: Ident -> FlatState VarIndex
lookupVarIndex id
   = do index_ <- gets (ScopeEnv.lookup id . varIdsE)
        maybe (internalError (missingVarIndex id)) return index_

--
clearVarIndices :: FlatState ()
clearVarIndices = modify (\env -> env { varIndexE = 0,
				        varIdsE = ScopeEnv.new 
				      })

--
genWarning :: String -> FlatState ()
genWarning msg
   = modify (\env -> env{ messagesE = warnMsg:(messagesE env) })
    where warnMsg = WarnMsg Nothing msg

--
genInterface :: FlatState Bool
genInterface = gets genInterfaceE

--
beginScope :: FlatState ()
beginScope = modify
	       (\env -> env { varIdsE  = ScopeEnv.beginScope (varIdsE env)
			    })

--
endScope :: FlatState ()
endScope = modify
	     (\env -> env { varIdsE  = ScopeEnv.endScope (varIdsE env)
			  })

--
whenFlatCurry :: FlatState a -> FlatState a -> FlatState a
whenFlatCurry genFlat genIntf 
   = genInterface >>= (\intf -> if intf then genIntf else genFlat)


-------------------------------------------------------------------------------

-- Generates an evironment containing all public identifiers from the module
-- Note: Currently the record functions (selection and update) for all public 
-- record labels are inserted into the environment, though they are not
-- explicitly declared in the export specifications.
genPubEnv :: ModuleIdent -> [CS.IDecl] -> Map.Map Ident IdentExport
genPubEnv mid idecls = foldl (bindEnvIDecl mid) Map.empty idecls

bindIdentExport :: Ident -> Bool -> Map.Map Ident IdentExport -> Map.Map Ident IdentExport
bindIdentExport id isConstr env =
    maybe (Map.insert id (if isConstr then OnlyConstr else NotConstr) env)
          (\ ie -> Map.insert id (updateIdentExport ie isConstr) env)
          (Map.lookup id env)
  where
    updateIdentExport OnlyConstr True  = OnlyConstr
    updateIdentExport OnlyConstr False = NotOnlyConstr
    updateIdentExport NotConstr True   = NotOnlyConstr
    updateIdentExport NotConstr False  = NotConstr
    updateIdentExport NotOnlyConstr _  = NotOnlyConstr


--
bindEnvIDecl :: ModuleIdent -> Map.Map Ident IdentExport -> CS.IDecl -> Map.Map Ident IdentExport
bindEnvIDecl mid env (CS.IDataDecl _ qid _ mcdecls)
   = maybe env 
           (\id -> foldl bindEnvConstrDecl
	                 (bindIdentExport id False env)
	                 (catMaybes mcdecls))
	   (localIdent mid qid)
bindEnvIDecl mid env (CS.INewtypeDecl _ qid _ ncdecl)
   = maybe env 
           (\id -> bindEnvNewConstrDecl (bindIdentExport id False env) ncdecl)
	   (localIdent mid qid)
bindEnvIDecl mid env (CS.ITypeDecl _ qid _ texpr)
   = maybe env (\id -> bindEnvITypeDecl env id texpr) (localIdent mid qid)
bindEnvIDecl mid env (CS.IFunctionDecl _ qid _ _)
   = maybe env (\id -> bindIdentExport id False env) (localIdent mid qid)
bindEnvIDecl _ env _ = env

--
bindEnvITypeDecl :: Map.Map Ident IdentExport -> Ident -> CS.TypeExpr
		    -> Map.Map Ident IdentExport
bindEnvITypeDecl env id (CS.RecordType fs _)
   = bindIdentExport id False (foldl (bindEnvRecordLabel id) env fs)
bindEnvITypeDecl env id texpr
   = bindIdentExport id False env

--
bindEnvConstrDecl :: Map.Map Ident IdentExport -> CS.ConstrDecl -> Map.Map Ident IdentExport
bindEnvConstrDecl env (CS.ConstrDecl _ _ id _)  = bindIdentExport id True env
bindEnvConstrDecl env (CS.ConOpDecl _ _ _ id _) = bindIdentExport id True env

--
bindEnvNewConstrDecl :: Map.Map Ident IdentExport -> CS.NewConstrDecl -> Map.Map Ident IdentExport
bindEnvNewConstrDecl env (CS.NewConstrDecl _ _ id _) = bindIdentExport id False env

--
bindEnvRecordLabel :: Ident -> Map.Map Ident IdentExport -> ([Ident],CS.TypeExpr) -> Map.Map Ident IdentExport
bindEnvRecordLabel r env ([lab], _) = bindIdentExport (recSelectorId (qualify r) lab) False expo
    where 
      expo = (bindIdentExport (recUpdateId (qualify r) lab) False env)


splitoffArgTypes :: IL.Type -> [Ident] -> [(Ident, IL.Type)]
splitoffArgTypes (IL.TypeArrow l r) (i:is) = (i, l):splitoffArgTypes r is
splitoffArgTypes _ [] = []
splitoffArgTypes _ _  = error "internal error in splitoffArgTypes"