//
// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// Unify.cc -- 
//
// Author           : Richard C. Bilson
// Created On       : Sun May 17 12:27:10 2015
// Last Modified By : Rob Schluntz
// Last Modified On : Wed Sep 02 14:43:22 2015
// Update Count     : 36
//

#include <set>
#include <memory>

#include "Unify.h"
#include "TypeEnvironment.h"
#include "typeops.h"
#include "FindOpenVars.h"
#include "SynTree/Visitor.h"
#include "SynTree/Type.h"
#include "SynTree/Declaration.h"
#include "SymTab/Indexer.h"
#include "Common/utility.h"


// #define DEBUG

namespace ResolvExpr {
	struct WidenMode {
		WidenMode( bool widenFirst, bool widenSecond ): widenFirst( widenFirst ), widenSecond( widenSecond ) {}
		WidenMode &operator|=( const WidenMode &other ) { widenFirst |= other.widenFirst; widenSecond |= other.widenSecond; return *this; }
		WidenMode &operator&=( const WidenMode &other ) { widenFirst &= other.widenFirst; widenSecond &= other.widenSecond; return *this; }
		WidenMode operator|( const WidenMode &other ) { WidenMode newWM( *this ); newWM |= other; return newWM; }
		WidenMode operator&( const WidenMode &other ) { WidenMode newWM( *this ); newWM &= other; return newWM; }
		operator bool() { return widenFirst && widenSecond; }
  
		bool widenFirst : 1, widenSecond : 1;
	};

	class Unify : public Visitor {
	  public:
		Unify( Type *type2, TypeEnvironment &env, AssertionSet &needAssertions, AssertionSet &haveAssertions, const OpenVarSet &openVars, WidenMode widenMode, const SymTab::Indexer &indexer );
  
		bool get_result() const { return result; }
	  private:
		virtual void visit(VoidType *voidType);
		virtual void visit(BasicType *basicType);
		virtual void visit(PointerType *pointerType);
		virtual void visit(ArrayType *arrayType);
		virtual void visit(FunctionType *functionType);
		virtual void visit(StructInstType *aggregateUseType);
		virtual void visit(UnionInstType *aggregateUseType);
		virtual void visit(EnumInstType *aggregateUseType);
		virtual void visit(ContextInstType *aggregateUseType);
		virtual void visit(TypeInstType *aggregateUseType);
		virtual void visit(TupleType *tupleType);

		template< typename RefType > void handleRefType( RefType *inst, Type *other );
		template< typename RefType > void handleGenericRefType( RefType *inst, Type *other );

		bool result;
		Type *type2;				// inherited
		TypeEnvironment &env;
		AssertionSet &needAssertions;
		AssertionSet &haveAssertions;
		const OpenVarSet &openVars;
		WidenMode widenMode;
		Type *commonType;
		const SymTab::Indexer &indexer;
	};

	/// Attempts an inexact unification of type1 and type2.
	/// Returns false if no such unification; if the types can be unified, sets common (unless they unify exactly and have identical type qualifiers)
	bool unifyInexact( Type *type1, Type *type2, TypeEnvironment &env, AssertionSet &needAssertions, AssertionSet &haveAssertions, const OpenVarSet &openVars, WidenMode widenMode, const SymTab::Indexer &indexer, Type *&common );
	bool unifyExact( Type *type1, Type *type2, TypeEnvironment &env, AssertionSet &needAssertions, AssertionSet &haveAssertions, const OpenVarSet &openVars, WidenMode widenMode, const SymTab::Indexer &indexer );
  
	bool typesCompatible( Type *first, Type *second, const SymTab::Indexer &indexer, const TypeEnvironment &env ) {
		TypeEnvironment newEnv;
		OpenVarSet openVars, closedVars; // added closedVars
		AssertionSet needAssertions, haveAssertions;
		Type *newFirst = first->clone(), *newSecond = second->clone();
		env.apply( newFirst );
		env.apply( newSecond );

		// do we need to do this? Seems like we do, types should be able to be compatible if they
		// have free variables that can unify
		findOpenVars( newFirst, openVars, closedVars, needAssertions, haveAssertions, false );
		findOpenVars( newSecond, openVars, closedVars, needAssertions, haveAssertions, true );

		bool result = unifyExact( newFirst, newSecond, newEnv, needAssertions, haveAssertions, openVars, WidenMode( false, false ), indexer );
		delete newFirst;
		delete newSecond;
		return result;
	}

	bool typesCompatibleIgnoreQualifiers( Type *first, Type *second, const SymTab::Indexer &indexer, const TypeEnvironment &env ) {
		TypeEnvironment newEnv;
		OpenVarSet openVars;
		AssertionSet needAssertions, haveAssertions;
		Type *newFirst = first->clone(), *newSecond = second->clone();
		env.apply( newFirst );
		env.apply( newSecond );
		newFirst->get_qualifiers() = Type::Qualifiers();
		newSecond->get_qualifiers() = Type::Qualifiers();
///   std::cout << "first is ";
///   first->print( std::cout );
///   std::cout << std::endl << "second is ";
///   second->print( std::cout );
///   std::cout << std::endl << "newFirst is ";
///   newFirst->print( std::cout );
///   std::cout << std::endl << "newSecond is ";
///   newSecond->print( std::cout );
///   std::cout << std::endl;
		bool result = unifyExact( newFirst, newSecond, newEnv, needAssertions, haveAssertions, openVars, WidenMode( false, false ), indexer );
		delete newFirst;
		delete newSecond;
		return result;
	}

	bool isFtype( Type *type, const SymTab::Indexer &indexer ) {
		if ( dynamic_cast< FunctionType* >( type ) ) {
			return true;
		} else if ( TypeInstType *typeInst = dynamic_cast< TypeInstType* >( type ) ) {
			return typeInst->get_isFtype();
		} // if
		return false;
	}

	bool tyVarCompatible( TypeDecl::Kind kind, Type *type, const SymTab::Indexer &indexer ) {
		switch ( kind ) {
		  case TypeDecl::Any:
		  case TypeDecl::Dtype:
			return ! isFtype( type, indexer );
  
		  case TypeDecl::Ftype:
			return isFtype( type, indexer );
		} // switch
		assert( false );
		return false;
	}

	bool bindVar( TypeInstType *typeInst, Type *other, TypeDecl::Kind kind, TypeEnvironment &env, AssertionSet &needAssertions, AssertionSet &haveAssertions, const OpenVarSet &openVars, WidenMode widenMode, const SymTab::Indexer &indexer ) {
		OpenVarSet::const_iterator tyvar = openVars.find( typeInst->get_name() );
		assert( tyvar != openVars.end() );
		if ( ! tyVarCompatible( tyvar->second, other, indexer ) ) {
			return false;
		} // if
		if ( occurs( other, typeInst->get_name(), env ) ) {
			return false;
		} // if
		EqvClass curClass;
		if ( env.lookup( typeInst->get_name(), curClass ) ) {
			if ( curClass.type ) {
				Type *common = 0;
				// attempt to unify equivalence class type (which has qualifiers stripped, so they must be restored) with the type to bind to
				std::auto_ptr< Type > newType( curClass.type->clone() );
				newType->get_qualifiers() = typeInst->get_qualifiers();
				if ( unifyInexact( newType.get(), other, env, needAssertions, haveAssertions, openVars, widenMode & WidenMode( curClass.allowWidening, true ), indexer, common ) ) {
					if ( common ) {
						common->get_qualifiers() = Type::Qualifiers();
						delete curClass.type;
						curClass.type = common;
						env.add( curClass );
					} // if
					return true;
				} else {
					return false;
				} // if
			} else {
				curClass.type = other->clone();
				curClass.type->get_qualifiers() = Type::Qualifiers();
				curClass.allowWidening = widenMode.widenFirst && widenMode.widenSecond;
				env.add( curClass );
			} // if
		} else {
			EqvClass newClass;
			newClass.vars.insert( typeInst->get_name() );
			newClass.type = other->clone();
			newClass.type->get_qualifiers() = Type::Qualifiers();
			newClass.allowWidening = widenMode.widenFirst && widenMode.widenSecond;
			newClass.kind = kind;
			env.add( newClass );
		} // if
		return true;
	}

	bool bindVarToVar( TypeInstType *var1, TypeInstType *var2, TypeDecl::Kind kind, TypeEnvironment &env, AssertionSet &needAssertions, AssertionSet &haveAssertions, const OpenVarSet &openVars, WidenMode widenMode, const SymTab::Indexer &indexer ) {
		bool result = true;
		EqvClass class1, class2;
		bool hasClass1 = false, hasClass2 = false;
		bool widen1 = false, widen2 = false;
		Type *type1 = 0, *type2 = 0;
  
		if ( env.lookup( var1->get_name(), class1 ) ) {
			hasClass1 = true;
			if ( class1.type ) {
				if ( occurs( class1.type, var2->get_name(), env ) ) {
					return false;
				} // if
				type1 = class1.type->clone();
			} // if
			widen1 = widenMode.widenFirst && class1.allowWidening;
		} // if
		if ( env.lookup( var2->get_name(), class2 ) ) {
			hasClass2 = true;
			if ( class2.type ) {
				if ( occurs( class2.type, var1->get_name(), env ) ) {
					return false;
				} // if
				type2 = class2.type->clone();
			} // if
			widen2 = widenMode.widenSecond && class2.allowWidening;
		} // if
  
		if ( type1 && type2 ) {
//    std::cout << "has type1 && type2" << std::endl;
			WidenMode newWidenMode ( widen1, widen2 );
			Type *common = 0;
			if ( unifyInexact( type1, type2, env, needAssertions, haveAssertions, openVars, newWidenMode, indexer, common ) ) {
				class1.vars.insert( class2.vars.begin(), class2.vars.end() );
				class1.allowWidening = widen1 && widen2;
				if ( common ) {
					common->get_qualifiers() = Type::Qualifiers();
					delete class1.type;
					class1.type = common;
				} // if
				env.add( class1 );
			} else {
				result = false;
			} // if
		} else if ( hasClass1 && hasClass2 ) {
			if ( type1 ) {
				class1.vars.insert( class2.vars.begin(), class2.vars.end() );
				class1.allowWidening = widen1;
				env.add( class1 );
			} else {
				class2.vars.insert( class1.vars.begin(), class1.vars.end() );
				class2.allowWidening = widen2;
				env.add( class2 );
			} // if
		} else if ( hasClass1 ) {
			class1.vars.insert( var2->get_name() );
			class1.allowWidening = widen1;
			env.add( class1 );
		} else if ( hasClass2 ) {
			class2.vars.insert( var1->get_name() );
			class2.allowWidening = widen2;
			env.add( class2 );
		} else {
			EqvClass newClass;
			newClass.vars.insert( var1->get_name() );
			newClass.vars.insert( var2->get_name() );
			newClass.allowWidening = widen1 && widen2;
			newClass.kind = kind;
			env.add( newClass );
		} // if
		delete type1;
		delete type2;
		return result;
	}

	bool unify( Type *type1, Type *type2, TypeEnvironment &env, AssertionSet &needAssertions, AssertionSet &haveAssertions, OpenVarSet &openVars, const SymTab::Indexer &indexer ) {
		OpenVarSet closedVars;
		findOpenVars( type1, openVars, closedVars, needAssertions, haveAssertions, false );
		findOpenVars( type2, openVars, closedVars, needAssertions, haveAssertions, true );
		Type *commonType = 0;
		if ( unifyInexact( type1, type2, env, needAssertions, haveAssertions, openVars, WidenMode( true, true ), indexer, commonType ) ) {
			if ( commonType ) {
				delete commonType;
			} // if
			return true;
		} else {
			return false;
		} // if
	}

	bool unify( Type *type1, Type *type2, TypeEnvironment &env, AssertionSet &needAssertions, AssertionSet &haveAssertions, OpenVarSet &openVars, const SymTab::Indexer &indexer, Type *&commonType ) {
		OpenVarSet closedVars;
		findOpenVars( type1, openVars, closedVars, needAssertions, haveAssertions, false );
		findOpenVars( type2, openVars, closedVars, needAssertions, haveAssertions, true );
		return unifyInexact( type1, type2, env, needAssertions, haveAssertions, openVars, WidenMode( true, true ), indexer, commonType );
	}

	bool unifyExact( Type *type1, Type *type2, TypeEnvironment &env, AssertionSet &needAssertions, AssertionSet &haveAssertions, const OpenVarSet &openVars, WidenMode widenMode, const SymTab::Indexer &indexer ) {
#ifdef DEBUG
		TypeEnvironment debugEnv( env );
#endif
		if ( type1->get_qualifiers() != type2->get_qualifiers() ) {
			return false;
		}

		bool result;
		TypeInstType *var1 = dynamic_cast< TypeInstType* >( type1 );
		TypeInstType *var2 = dynamic_cast< TypeInstType* >( type2 );
		OpenVarSet::const_iterator entry1, entry2;
		if ( var1 ) {
			entry1 = openVars.find( var1->get_name() );
		} // if
		if ( var2 ) {
			entry2 = openVars.find( var2->get_name() );
		} // if
		bool isopen1 = var1 && ( entry1 != openVars.end() );
		bool isopen2 = var2 && ( entry2 != openVars.end() );

		if ( isopen1 && isopen2 && entry1->second == entry2->second ) {
			result = bindVarToVar( var1, var2, entry1->second, env, needAssertions, haveAssertions, openVars, widenMode, indexer );
		} else if ( isopen1 ) {
			result = bindVar( var1, type2, entry1->second, env, needAssertions, haveAssertions, openVars, widenMode, indexer );
		} else if ( isopen2 ) {
			result = bindVar( var2, type1, entry2->second, env, needAssertions, haveAssertions, openVars, widenMode, indexer );
		} else {
			Unify comparator( type2, env, needAssertions, haveAssertions, openVars, widenMode, indexer );
			type1->accept( comparator );
			result = comparator.get_result();
		} // if
#ifdef DEBUG
		std::cout << "============ unifyExact" << std::endl;
		std::cout << "type1 is ";
		type1->print( std::cout );
		std::cout << std::endl << "type2 is ";
		type2->print( std::cout );
		std::cout << std::endl << "openVars are ";
		printOpenVarSet( openVars, std::cout, 8 );
		std::cout << std::endl << "input env is " << std::endl;
		debugEnv.print( std::cout, 8 );
		std::cout << std::endl << "result env is " << std::endl;
		env.print( std::cout, 8 );
		std::cout << "result is " << result << std::endl;
#endif
		return result;
	}

	bool unifyExact( Type *type1, Type *type2, TypeEnvironment &env, AssertionSet &needAssertions, AssertionSet &haveAssertions, OpenVarSet &openVars, const SymTab::Indexer &indexer ) {
		return unifyExact( type1, type2, env, needAssertions, haveAssertions, openVars, WidenMode( false, false ), indexer );
	}

	bool unifyInexact( Type *type1, Type *type2, TypeEnvironment &env, AssertionSet &needAssertions, AssertionSet &haveAssertions, const OpenVarSet &openVars, WidenMode widenMode, const SymTab::Indexer &indexer, Type *&common ) {
		Type::Qualifiers tq1 = type1->get_qualifiers(), tq2 = type2->get_qualifiers();
		type1->get_qualifiers() = Type::Qualifiers();
		type2->get_qualifiers() = Type::Qualifiers();
		bool result;
#ifdef DEBUG
		std::cout << "unifyInexact type 1 is ";
		type1->print( std::cout );
		std::cout << "type 2 is ";
		type2->print( std::cout );
		std::cout << std::endl;
#endif
		if ( ! unifyExact( type1, type2, env, needAssertions, haveAssertions, openVars, widenMode, indexer ) ) {
#ifdef DEBUG
			std::cout << "unifyInexact: no exact unification found" << std::endl;
#endif
			if ( ( common = commonType( type1, type2, widenMode.widenFirst, widenMode.widenSecond, indexer, env, openVars ) ) ) {
				common->get_qualifiers() = tq1 + tq2;
#ifdef DEBUG
				std::cout << "unifyInexact: common type is ";
				common->print( std::cout );
				std::cout << std::endl;
#endif
				result = true;
			} else {
#ifdef DEBUG
				std::cout << "unifyInexact: no common type found" << std::endl;
#endif
				result = false;
			} // if
		} else {
			if ( tq1 != tq2 ) {
				if ( ( tq1 > tq2 || widenMode.widenFirst ) && ( tq2 > tq1 || widenMode.widenSecond ) ) {
					common = type1->clone();
					common->get_qualifiers() = tq1 + tq2;
					result = true;
				} else {
					result = false;
				} // if
			} else {
				result = true;
			} // if
		} // if
		type1->get_qualifiers() = tq1;
		type2->get_qualifiers() = tq2;
		return result;
	}

	Unify::Unify( Type *type2, TypeEnvironment &env, AssertionSet &needAssertions, AssertionSet &haveAssertions, const OpenVarSet &openVars, WidenMode widenMode, const SymTab::Indexer &indexer )
		: result( false ), type2( type2 ), env( env ), needAssertions( needAssertions ), haveAssertions( haveAssertions ), openVars( openVars ), widenMode( widenMode ), indexer( indexer ) {
	}

	void Unify::visit(VoidType *voidType) {
		result = dynamic_cast< VoidType* >( type2 );
	}

	void Unify::visit(BasicType *basicType) {
		if ( BasicType *otherBasic = dynamic_cast< BasicType* >( type2 ) ) {
			result = basicType->get_kind() == otherBasic->get_kind();
		} // if
	}

	void markAssertionSet( AssertionSet &assertions, DeclarationWithType *assert ) {
///   std::cout << "assertion set is" << std::endl;
///   printAssertionSet( assertions, std::cout, 8 );
///   std::cout << "looking for ";
///   assert->print( std::cout );
///   std::cout << std::endl;
		AssertionSet::iterator i = assertions.find( assert );
		if ( i != assertions.end() ) {
///     std::cout << "found it!" << std::endl;
			i->second = true;
		} // if
	}

	void markAssertions( AssertionSet &assertion1, AssertionSet &assertion2, Type *type ) {
		for ( std::list< TypeDecl* >::const_iterator tyvar = type->get_forall().begin(); tyvar != type->get_forall().end(); ++tyvar ) {
			for ( std::list< DeclarationWithType* >::const_iterator assert = (*tyvar)->get_assertions().begin(); assert != (*tyvar)->get_assertions().end(); ++assert ) {
				markAssertionSet( assertion1, *assert );
				markAssertionSet( assertion2, *assert );
			} // for
		} // for
	}

	void Unify::visit(PointerType *pointerType) {
		if ( PointerType *otherPointer = dynamic_cast< PointerType* >( type2 ) ) {
			result = unifyExact( pointerType->get_base(), otherPointer->get_base(), env, needAssertions, haveAssertions, openVars, WidenMode( false, false ), indexer );
			markAssertions( haveAssertions, needAssertions, pointerType );
			markAssertions( haveAssertions, needAssertions, otherPointer );
		} // if
	}

	void Unify::visit(ArrayType *arrayType) {
		ArrayType *otherArray = dynamic_cast< ArrayType* >( type2 );
		// to unify, array types must both be VLA or both not VLA
		// and must both have a dimension expression or not have a dimension
		if ( otherArray && arrayType->get_isVarLen() == otherArray->get_isVarLen() 
				&& ((arrayType->get_dimension() != 0 && otherArray->get_dimension() != 0)
					|| (arrayType->get_dimension() == 0 && otherArray->get_dimension() == 0))) {

			// not positive this is correct in all cases, but it's needed for typedefs
			if ( arrayType->get_isVarLen() || otherArray->get_isVarLen() ) {
				return;
			}

			if ( ! arrayType->get_isVarLen() && ! otherArray->get_isVarLen() &&
				arrayType->get_dimension() != 0 && otherArray->get_dimension() != 0 ) {
				ConstantExpr * ce1 = dynamic_cast< ConstantExpr * >( arrayType->get_dimension() );
				ConstantExpr * ce2 = dynamic_cast< ConstantExpr * >( otherArray->get_dimension() );
				assert(ce1 && ce2);

				Constant * c1 = ce1->get_constant();
				Constant * c2 = ce2->get_constant();

				if ( c1->get_value() != c2->get_value() ) {
					// does not unify if the dimension is different
					return;
				}
			}

			result = unifyExact( arrayType->get_base(), otherArray->get_base(), env, needAssertions, haveAssertions, openVars, WidenMode( false, false ), indexer );
		} // if
	}

	template< typename Iterator1, typename Iterator2 >
	bool unifyDeclList( Iterator1 list1Begin, Iterator1 list1End, Iterator2 list2Begin, Iterator2 list2End, TypeEnvironment &env, AssertionSet &needAssertions, AssertionSet &haveAssertions, const OpenVarSet &openVars, const SymTab::Indexer &indexer ) {
		for ( ; list1Begin != list1End && list2Begin != list2End; ++list1Begin, ++list2Begin ) {
			// Type * commonType;
			// if ( ! unifyInexact( (*list1Begin)->get_type(), (*list2Begin)->get_type(), env, needAssertions, haveAssertions, openVars, WidenMode( true, true ), indexer, commonType ) ) {
			if ( ! unifyExact( (*list1Begin)->get_type(), (*list2Begin)->get_type(), env, needAssertions, haveAssertions, openVars, WidenMode( false, false ), indexer ) ) {
				return false;
			} // if
		} // for
		if ( list1Begin != list1End || list2Begin != list2End ) {
			return false;
		} else {
			return true;
		} // if
	}

	void Unify::visit(FunctionType *functionType) {
		FunctionType *otherFunction = dynamic_cast< FunctionType* >( type2 );
		if ( otherFunction && functionType->get_isVarArgs() == otherFunction->get_isVarArgs() ) {

			if ( unifyDeclList( functionType->get_parameters().begin(), functionType->get_parameters().end(), otherFunction->get_parameters().begin(), otherFunction->get_parameters().end(), env, needAssertions, haveAssertions, openVars, indexer ) ) {
	
				if ( unifyDeclList( functionType->get_returnVals().begin(), functionType->get_returnVals().end(), otherFunction->get_returnVals().begin(), otherFunction->get_returnVals().end(), env, needAssertions, haveAssertions, openVars, indexer ) ) {

					markAssertions( haveAssertions, needAssertions, functionType );
					markAssertions( haveAssertions, needAssertions, otherFunction );

					result = true;
				} // if
			} // if
		} // if
	}

	template< typename RefType >
	void Unify::handleRefType( RefType *inst, Type *other ) {
		// check that other type is compatible and named the same
		RefType *otherStruct = dynamic_cast< RefType* >( other );
		result = otherStruct && inst->get_name() == otherStruct->get_name();
	}

	template< typename RefType >
	void Unify::handleGenericRefType( RefType *inst, Type *other ) {
		// Check that other type is compatible and named the same
		handleRefType( inst, other );
		if ( ! result ) return;
		// Check that parameters of types unify, if any
		std::list< Expression* > params = inst->get_parameters();
		std::list< Expression* > otherParams = ((RefType*)other)->get_parameters();

		std::list< Expression* >::const_iterator it = params.begin(), jt = otherParams.begin();
		for ( ; it != params.end() && jt != otherParams.end(); ++it, ++jt ) {
			TypeExpr *param = dynamic_cast< TypeExpr* >(*it);
			assert(param && "Aggregate parameters should be type expressions");
			TypeExpr *otherParam = dynamic_cast< TypeExpr* >(*jt);
			assert(otherParam && "Aggregate parameters should be type expressions");

			if ( ! unifyExact( param->get_type(), otherParam->get_type(), env, needAssertions, haveAssertions, openVars, WidenMode(false, false), indexer ) ) {
				result = false;
				return;
			}
		}
		result = ( it == params.end() && jt == otherParams.end() );
	}

	void Unify::visit(StructInstType *structInst) {
		handleGenericRefType( structInst, type2 );
	}

	void Unify::visit(UnionInstType *unionInst) {
		handleGenericRefType( unionInst, type2 );
	}

	void Unify::visit(EnumInstType *enumInst) {
		handleRefType( enumInst, type2 );
	}

	void Unify::visit(ContextInstType *contextInst) {
		handleRefType( contextInst, type2 );
	}

	void Unify::visit(TypeInstType *typeInst) {
		assert( openVars.find( typeInst->get_name() ) == openVars.end() );
		TypeInstType *otherInst = dynamic_cast< TypeInstType* >( type2 );
		if ( otherInst && typeInst->get_name() == otherInst->get_name() ) {
			result = true;
///   } else {
///     NamedTypeDecl *nt = indexer.lookupType( typeInst->get_name() );
///     if ( nt ) {
///       TypeDecl *type = dynamic_cast< TypeDecl* >( nt );
///       assert( type );
///       if ( type->get_base() ) {
///         result = unifyExact( type->get_base(), typeInst, env, needAssertions, haveAssertions, openVars, WidenMode( false, false ), indexer );
///       }
///     }
		} // if
	}

	template< typename Iterator1, typename Iterator2 >
	bool unifyList( Iterator1 list1Begin, Iterator1 list1End, Iterator2 list2Begin, Iterator2 list2End, TypeEnvironment &env, AssertionSet &needAssertions, AssertionSet &haveAssertions, const OpenVarSet &openVars, WidenMode widenMode, const SymTab::Indexer &indexer ) {
		for ( ; list1Begin != list1End && list2Begin != list2End; ++list1Begin, ++list2Begin ) {
			Type *commonType = 0;
			if ( ! unifyInexact( *list1Begin, *list2Begin, env, needAssertions, haveAssertions, openVars, widenMode, indexer, commonType ) ) {
				return false;
			}
			delete commonType;
		} // for
		if ( list1Begin != list1End || list2Begin != list2End ) {
			return false;
		} else {
			return true;
		} //if
	}

	void Unify::visit(TupleType *tupleType) {
		if ( TupleType *otherTuple = dynamic_cast< TupleType* >( type2 ) ) {
			result = unifyList( tupleType->get_types().begin(), tupleType->get_types().end(), otherTuple->get_types().begin(), otherTuple->get_types().end(), env, needAssertions, haveAssertions, openVars, widenMode, indexer );
		} // if
	}

} // namespace ResolvExpr

// Local Variables: //
// tab-width: 4 //
// mode: c++ //
// compile-command: "make install" //
// End: //