syntax.icl

implementation module syntax

import StdEnv, compare_constructor // ,RWSDebug

import scanner, general, Heap, typeproperties, utilities, compilerSwitches

::	Ident =
	{ 	id_name		:: !String
	,	id_info 	:: !SymbolPtr
	}

instance toString Ident
where toString {id_name} = id_name

instance toString (Import from_symbol)
where toString {import_module} = toString import_module


/*	Each Identifier is equipped with a pointer to a SymbolTableEntry that is
	used for binding the identifier with its definition.
*/

::	SymbolTable			:== Heap SymbolTableEntry
::	SymbolPtr 			:== Ptr SymbolTableEntry

::	SymbolTableEntry = 
	{	ste_kind		:: !STE_Kind
	,	ste_index		:: !Index
	,	ste_def_level	:: !Level
	,	ste_previous	:: SymbolTableEntry
	}

::	STE_BoundTypeVariable	= { stv_count :: !Int, stv_attribute :: !TypeAttribute, stv_info_ptr :: !TypeVarInfoPtr /* TD */, stv_position :: Int }

::	STE_Kind	= STE_FunctionOrMacro ![Index]
				| STE_Type
				| STE_Constructor
				| STE_Selector ![Global Index]
				| STE_Field !Ident
				| STE_Class
				| STE_Member
				| STE_Generic			// AA: For generic declarations
				| STE_Instance !Ident // the class (for explicit imports (1.3 syntax only))
				| STE_Variable !VarInfoPtr
				| STE_TypeVariable !TypeVarInfoPtr
				| STE_TypeAttribute !AttrVarInfoPtr
				| STE_BoundTypeVariable !STE_BoundTypeVariable
				| STE_Imported !STE_Kind !Index
				| STE_DclFunction
				| STE_Module !(Module (CollectedDefinitions ClassInstance IndexRange))
				| STE_ClosedModule
				| STE_Empty 
				| STE_DictType !CheckedTypeDef
				| STE_DictCons !ConsDef
				| STE_DictField !SelectorDef
				| STE_Called ![Index] /* used during macro expansion to indicate that this function is called */
				| STE_ExplImpSymbol !Int
				| STE_ExplImpComponentNrs ![ComponentNrAndIndex] ![Declaration]
				| STE_BelongingSymbol !Int

::	Declaration = Declaration !DeclarationRecord

::	DeclarationRecord =
	{	decl_ident	:: !Ident
	,	decl_pos	:: !Position
	,	decl_kind	:: !STE_Kind
	,	decl_index	:: !Index
	}

::	ComponentNrAndIndex =
	{	cai_component_nr	:: !Int
	,	cai_index			:: !Int
	}

::	Global object =
	{	glob_object	:: !object
	,	glob_module	:: !Index
	}
	
::	Module defs = 
	{	mod_name		:: !Ident
	,	mod_type		:: !ModuleKind
	, 	mod_imports		:: ![ParsedImport]
	,	mod_imported_objects :: ![ImportedObject]
	,	mod_defs		:: !defs
	}

::	ParsedModule	:== Module  [ParsedDefinition]
::	ScannedModule 	:== Module  (CollectedDefinitions (ParsedInstance FunDef) IndexRange)

::	ModuleKind	= MK_Main | MK_Module | MK_System | MK_None

::	RhsDefsOfType	= ConsList ![ParsedConstructor]
					| SelectorList !Ident ![ATypeVar] ![ParsedSelector]
					| TypeSpec !AType
					| EmptyRhs !BITVECT

::	CollectedDefinitions instance_kind macro_defs =
	{	def_types 			:: ![TypeDef TypeRhs]
	,	def_constructors	:: ![ConsDef]
	,	def_selectors		:: ![SelectorDef]
	,	def_macros			:: !macro_defs
	,	def_classes			:: ![ClassDef]
	,	def_members			:: ![MemberDef]
	,	def_generics		:: ![GenericDef] // AA
	,	def_funtypes		:: ![FunType]
	,	def_instances		:: ![instance_kind]
	}

::	LocalDefs = LocalParsedDefs [ParsedDefinition] | CollectedLocalDefs CollectedLocalDefs

::	IndexRange	= { ir_from :: !Index, ir_to :: !Index }

::  Index	:== Int
NoIndex		:== -1


::  Level	:== Int
NotALevel 	:==  -1

::	CollectedLocalDefs =
	{	loc_functions	:: !IndexRange
	,	loc_nodes		:: ![NodeDef ParsedExpr]
	}

::	NodeDef dst =
	{	nd_dst		::!dst,
		nd_alts		::!OptGuardedAlts,
		nd_locals	::!LocalDefs,
		nd_position	::!Position		
	}

::	Rhs =
	{	rhs_alts	:: !OptGuardedAlts
	,	rhs_locals	:: !LocalDefs
	}

cIsAFunction	:== True
cIsNotAFunction :== False

::	ParsedDefinition 
	=	PD_Function  Position Ident Bool [ParsedExpr] Rhs FunKind
	|	PD_NodeDef  Position ParsedExpr Rhs
	|	PD_Type ParsedTypeDef
	|	PD_TypeSpec Position Ident Priority (Optional SymbolType) Specials
	|	PD_Class ClassDef [ParsedDefinition]
	|	PD_Generic GenericDef // AA
	|	PD_Instance (ParsedInstance ParsedDefinition)
	|	PD_Instances [ParsedInstance ParsedDefinition]
	|	PD_Import [ParsedImport]
	|	PD_ImportedObjects [ImportedObject]
	|	PD_Erroneous

::	FunKind	= FK_Function !Bool | FK_Macro | FK_Caf | FK_Unknown

::	DefOrImpFunKind = FK_DefFunction !Bool| FK_ImpFunction !Bool | FK_DefMacro | FK_ImpMacro | FK_ImpCaf | FK_DefOrImpUnknown

cNameNotLocationDependent :== False
cNameLocationDependent :== True

::	ParsedSelector =
	{	ps_field_name		:: !Ident
	,	ps_selector_name	:: !Ident
	,	ps_field_type		:: !AType
	,	ps_field_var		:: !Ident
	,	ps_field_pos		:: !Position
	}

::	ParsedConstructor =
	{	pc_cons_name 	:: !Ident
	,	pc_cons_arity	:: !Int
	,	pc_exi_vars		:: ![ATypeVar]
	,	pc_arg_types	:: ![AType]
	,	pc_cons_prio	:: !Priority
	,	pc_cons_pos		:: !Position
	}
	
::	ParsedInstance member =
	{	pi_class 	:: !Ident
	,	pi_ident	:: !Ident
	,	pi_types	:: ![Type]
	,	pi_context	:: ![TypeContext]
	,	pi_pos		:: !Position
	,	pi_members	:: ![member]
	,	pi_specials	:: !Specials
	,	pi_generate  :: !Bool // AA: instance is to be generated
	}


::	Specials
	= SP_ParsedSubstitutions 	![Env Type TypeVar]
	| SP_Substitutions 		 	![SpecialSubstitution]
	| SP_ContextTypes			![Special]
	| SP_FunIndex				!Index
	| SP_TypeOffset				!Int
	| SP_None

::	SpecialSubstitution =
	{	ss_environ	:: !Env Type TypeVar
	,	ss_context	:: ![TypeContext]
	,	ss_vars		:: ![TypeVar]
	,	ss_attrs	:: ![AttributeVar]
	}

::	Special =
	{	spec_index	:: !Global Index
	,	spec_types	:: ![[Type]]
	,	spec_vars	:: ![TypeVar]
	, 	spec_attrs	:: ![AttributeVar]
	}


::	AttrInequality =
	{	ai_demanded :: !AttributeVar
	,	ai_offered	:: !AttributeVar
	}

::	DefinedSymbol = 
	{	ds_ident		:: !Ident
	,	ds_arity		:: !Int
	,	ds_index		:: !Index
	}

::	ClassSymbIdent =
	{	cs_name		:: !Ident
	,	cs_arity 	:: !Int
	,	cs_index 	:: !Int
	}

::	ClassDef =
 	{	class_name			:: !Ident
	,	class_arity			:: !Int
	,	class_args			:: ![TypeVar]
	,	class_context		:: ![TypeContext]
	,	class_members		:: !{# DefinedSymbol}
	,	class_dictionary	:: !DefinedSymbol
	,	class_pos			:: !Position
	,	class_cons_vars		:: !BITVECT
	}

::	MemberDef =
	{	me_symb			:: !Ident
	,	me_class		:: !Global Index
	,	me_offset		:: !Index
	,	me_type			:: !SymbolType
	,	me_type_ptr		:: !VarInfoPtr
	,	me_class_vars	:: ![TypeVar]
	,	me_pos			:: !Position
	,	me_priority 	:: !Priority
	}

// AA.. 
::	GenericDef = 
	{	gen_name		:: !Ident	// the generics name in IC_Class 
	,	gen_member_name	:: !Ident	// the generics name in IC_Member
	,	gen_type		:: !GenericType
	, 	gen_pos			:: !Position
	,	gen_kinds_ptr	:: !TypeVarInfoPtr		// hack: contains all used kinds 
	,	gen_cons_ptr 	:: !TypeVarInfoPtr		// hack: cons instance function
	, 	gen_classes		:: !GenericClassInfos 	// generated classes
	,	gen_isomap		:: !DefinedSymbol		// isomap function
	}

:: GenericType = 
	{	gt_type 		:: !SymbolType
	,	gt_vars			:: ![TypeVar]			// generic arguments
	,	gt_arity		:: !Int					// number of generic arguments	
	}

:: GenericClassInfo = 
	{	gci_kind 	:: !TypeKind
	,	gci_class	:: !DefinedSymbol
	}
:: GenericClassInfos :== [GenericClassInfo] 	 

getGenericClassForKind 	:: !GenericDef !TypeKind -> (!Bool, DefinedSymbol)
getGenericClassForKind	{gen_classes} kind
	= get_class gen_classes kind
where
	get_class [] kind 
		= (False, undef)
	get_class [{gci_kind, gci_class}:gcis] kind
		| gci_kind == kind	= (True, gci_class)	 
		| otherwise			= get_class gcis kind
	
addGenericKind :: !GenericDef !TypeKind -> !GenericDef
addGenericKind generic_def=:{gen_name, gen_classes} kind 
	#(ok, _) = getGenericClassForKind generic_def kind
	| ok = generic_def
	# class_ds = 
		{	ds_ident = {id_name = gen_name.id_name +++ ":" +++ toString kind, id_info = nilPtr}
		, 	ds_index = NoIndex
		,	ds_arity = 1
		}
	= {generic_def & gen_classes = [{gci_kind = kind, gci_class = class_ds}:gen_classes]} 	

// ..AA

::	InstanceType =
	{	it_vars			:: [TypeVar]
	,	it_types		:: ![Type]
	,	it_attr_vars	:: [AttributeVar]
	,	it_context		:: ![TypeContext]
	}

::	ClassInstance =
 	{	ins_class		:: !Global DefinedSymbol
	,	ins_ident		:: !Ident
	,	ins_type		:: !InstanceType
	,	ins_members		:: !{# DefinedSymbol}
	,	ins_specials	:: !Specials
	,	ins_pos			:: !Position
	,	ins_is_generic	:: !Bool			//AA 
	, 	ins_generate	:: !Bool			//AA
	,	ins_partial		:: !Bool			//AA
	,	ins_generic		:: !Global Index	//AA
	}

::	Import from_symbol =
	{	import_module		:: !Ident
	,	import_symbols		:: ![from_symbol]
	,	import_file_position:: !Position	// for error messages
	}

::	ParsedImport		:== Import ImportDeclaration

::	ImportedIdent =
	{	ii_ident	:: !Ident
	,	ii_extended	:: !Bool
	}

::	ImportDeclaration	= ID_Function !ImportedIdent
						| ID_Class !ImportedIdent !(Optional [ImportedIdent])
						| ID_Type !ImportedIdent !(Optional [ImportedIdent])
						| ID_Record !ImportedIdent !(Optional [ImportedIdent])
						| ID_Instance !ImportedIdent !Ident !(![Type],![TypeContext])
						| ID_OldSyntax ![Ident]

cIsImportedLibrary :== True
cIsImportedObject :== False
:: ImportedObject =
	{	io_is_library :: !Bool
	,	io_name    :: !{#Char}
	}

::	RecordType =
	{	rt_constructor	:: !DefinedSymbol
	,	rt_fields		:: !{# FieldSymbol}
	}
	
::	FieldSymbol =
	{	fs_name			:: !Ident
	,	fs_var			:: !Ident
	,	fs_index		:: !Index
	}


::	TypeRhs	= AlgType ![DefinedSymbol]
			| SynType !AType
			| RecordType !RecordType
			| AbstractType !BITVECT
			| UnknownType

::	ParsedTypeDef :== TypeDef RhsDefsOfType
::	CheckedTypeDef :== TypeDef TypeRhs

cAllBitsClear			:== 0

cIsHyperStrict			:== 1
cIsNonCoercible			:== 2
cMayBeNonCoercible		:== 4

::	TypeDef type_rhs =
 	{	td_name			:: !Ident
	,	td_index		:: !Int
	,	td_arity		:: !Int
	,	td_args			:: ![ATypeVar]
	,	td_attrs		:: ![AttributeVar]
	,	td_context		:: ![TypeContext]
	,	td_rhs			:: !type_rhs
	,	td_attribute	:: !TypeAttribute
	,	td_pos			:: !Position
	}

::	FunType =
	{	ft_symb			:: !Ident
	,	ft_arity		:: !Int
	,	ft_priority		:: !Priority
	,	ft_type			:: !SymbolType
	,	ft_pos			:: !Position
	,	ft_specials		:: !Specials
	,	ft_type_ptr		:: !VarInfoPtr
	}

::	FreeVar =
	{	fv_def_level	:: !Level
	,	fv_name			:: !Ident
	,	fv_info_ptr		:: !VarInfoPtr
	,	fv_count		:: !Int
	}
	
::	FunCall =
	{	fc_level		:: !Level
	,	fc_index		:: !Index
	}

/* Sjaak 19-3-2001 ... */

FI_IsMacroFun	:== 1			// whether the function is a local function of a macro
FI_HasTypeSpec	:== 2			// whether the function has u user defined type

::	FunInfo =
	{	fi_calls			:: ![FunCall]
	,	fi_group_index		:: !Index
	,	fi_def_level		:: !Level
	,	fi_free_vars		:: ![FreeVar]
	,	fi_local_vars		:: ![FreeVar]
	,	fi_dynamics			:: ![ExprInfoPtr]
	,	fi_properties		:: !BITVECT
	}
/* ... Sjaak 19-3-2001 */

::	ParsedBody =
	{	pb_args	:: ![ParsedExpr]
	,	pb_rhs	:: !Rhs
	,	pb_position	:: !Position
	}

::	CheckedBody =
	{	cb_args		:: ![FreeVar]
	,	cb_rhs		:: ![CheckedAlternative]
	}

::	CheckedAlternative =
	{	ca_rhs		:: !Expression
	,	ca_position	:: !Position	// the position is NoPos iff the position information for this
	}								// alternative is already stored in a case alternative
									// (in ap_position, bp_position or dp_position)

::	TransformedBody =
	{	tb_args			:: ![FreeVar]
	,	tb_rhs			:: !Expression
	}

::	FunctionBody	= ParsedBody ![ParsedBody]
					| CheckedBody !CheckedBody
	/* The next three constructors are used during macro expansion (module transform) */
					| PartioningMacro
					| PartioningFunction !CheckedBody !Int
					| RhsMacroBody !CheckedBody
	/* macro expansion the transforms a CheckedBody into a TransformedBody */
					| TransformedBody !TransformedBody
					| Expanding ![FreeVar] // the parameters of the newly generated function
					| BackendBody ![BackendBody]
					| NoBody
					
::	BackendBody =
	{	bb_args	:: ![FunctionPattern]
	,	bb_rhs	:: !Expression
	}

::	FunDef =
	{	fun_symb		:: !Ident
	,	fun_arity		:: !Int
	,	fun_priority	:: !Priority
	,	fun_body		:: !FunctionBody
	,	fun_type		:: !Optional SymbolType
	,	fun_pos			:: !Position
	,	fun_index		:: !Int
	,	fun_kind		:: !DefOrImpFunKind
	,	fun_lifted		:: !Int
//	,	fun_type_ptr	:: !TypeVarInfoPtr
	,	fun_info		:: !FunInfo
	}

cIsAGlobalVar	:== True
cIsALocalVar	:== False

::	ConsClasses =
	{	cc_size			::!Int
	,	cc_args			::![ConsClass]
	,	cc_linear_bits	::![Bool]
	}
					
::	ConsClass	:== Int

::	OptionalVariable :== Optional (Bind Ident VarInfoPtr)

:: 	AuxiliaryPattern
		= AP_Algebraic !(Global DefinedSymbol) !Index [AuxiliaryPattern] OptionalVariable
		| AP_Variable !Ident !VarInfoPtr OptionalVariable
		| AP_Basic !BasicValue OptionalVariable
		| AP_Dynamic !AuxiliaryPattern !DynamicType !OptionalVariable
		| AP_Constant !AP_Kind !(Global DefinedSymbol) !Priority
		| AP_WildCard !OptionalVariable
		| AP_Empty !Ident

:: AP_Kind = APK_Constructor !Index | APK_Macro

::	VarInfo  =	VI_Empty |VI_Type !AType !(Optional CoercionPosition) | VI_Occurrence !Occurrence | VI_UsedVar !Ident |
				VI_Expression !Expression | VI_Variable !Ident !VarInfoPtr | VI_LiftedVariable !VarInfoPtr |
				VI_Count !Int /* the reference count of a variable */ !Bool /* true if the variable is global, false otherwise */ |
				VI_AccVar !ConsClass !ArgumentPosition /* used during fusion to determine accumulating parameters of functions */ |
				VI_Alias !BoundVar /* used for resolving aliases just before type checking (in transform) */ |
				 /* used during elimination and lifting of cases */
				VI_FreeVar !Ident !VarInfoPtr !Int !AType | VI_BoundVar !AType | VI_LocalVar |
				VI_ClassVar !Ident !VarInfoPtr !Int | /* to hold dictionary variables during overloading */
				VI_ForwardClassVar !VarInfoPtr | /* to hold the dictionary variable generated during overloading */
				VI_Forward !BoundVar | VI_LetVar !LetVarInfo | VI_LetExpression !LetExpressionInfo | VI_CaseVar !VarInfoPtr |
				VI_CorrespondenceNumber !Int | /* it is assumed that this alternative is _only_ used in module comparedefimp */
				VI_SequenceNumber !Int |
				VI_Used | /* for indicating that an imported function has been used */
				VI_PropagationType !SymbolType | /* for storing the type with propagation environment of an imported function */
				VI_ExpandedType !SymbolType | /* for storing the (expanded) type of an imported function */
				VI_Record ![AuxiliaryPattern] |
				VI_Pattern !AuxiliaryPattern |
				VI_Default !Int | VI_Indirection !Int | /* used during conversion of dynamics; the Int indiacted the refenrence count */
				VI_Body !SymbIdent !TransformedBody ![FreeVar] | /* used during fusion */
				VI_Dictionary !SymbIdent ![Expression] !Type | /* used during fusion */
				VI_Extended !ExtendedVarInfo !VarInfo |
				VI_Defined /* for marking type code variables during overloading */ | VI_LocallyDefined |
// MdM
				VI_CPSLocalExprVar !Int /* MdM - the index of the variable as generated by the theorem prover */
// ... MdM
				| VI_Labelled_Empty {#Char} // RWS debugging
				| VI_LocalLetVar // RWS, mark Let vars during case transformation

::	ExtendedVarInfo = EVI_VarType !AType

::	ArgumentPosition :== Int

::	VarInfoPtr	:== Ptr VarInfo

::	LetVarInfo =
	{	lvi_count		:: !Int
	,	lvi_depth		:: !Int
	,	lvi_new			:: !Bool
	,	lvi_var			:: !Ident
	,	lvi_expression	:: !Expression	
	,   lvi_previous	:: ![PreviousLetVarInfo]
	}

::	PreviousLetVarInfo =
	{	plvi_count		:: !Int
	,	plvi_depth		:: !Int
	,	plvi_new		:: !Bool
	}

::	LetExpressionStatus	= LES_Untouched | LES_Moved | LES_Updated !Expression

::	LetExpressionInfo =
	{	lei_count			:: !Int
	,	lei_depth			:: !Int 
	,	lei_var				:: !FreeVar 
	,   lei_expression		:: !Expression
	,   lei_status			:: !LetExpressionStatus
	,   lei_type			:: !AType
	}

cNotVarNumber :== -1

::	BoundVar = 
	{	var_name		:: !Ident
	,	var_info_ptr	:: !VarInfoPtr
	,	var_expr_ptr	:: !ExprInfoPtr
	}

::	TypeSymbIdent =
	{	type_name		:: !Ident
	,	type_arity		:: !Int
	,	type_index		:: !Global Index
	,	type_prop		:: !TypeSymbProperties
	}

::	TypeSymbProperties =
	{	tsp_sign		:: !SignClassification
	,	tsp_propagation	:: !PropClassification
	,	tsp_coercible	:: !Bool
	}

::	SymbKind	= SK_Unknown
				| SK_Function !(Global Index)
				| SK_LocalMacroFunction !Index
				| SK_OverloadedFunction !(Global Index)
				| SK_Generic !(Global Index) !TypeKind		// AA
				| SK_Constructor !(Global Index)
				| SK_Macro !(Global Index)
//				| SK_RecordSelector !(Global Index)
				| SK_GeneratedFunction !FunctionInfoPtr !Index
				| SK_TypeCode

// MW2 moved some type definitions

/*	Some auxiliary type definitions used during fusion. Actually, these definitions
	should have beengiven in seperate module. Unfortunately, Clean's module system
	forbids cyclic dependencies between def modules.
	
*/

::	FunctionHeap 	:== Heap FunctionInfo

::	FunctionInfoPtr	:== Ptr FunctionInfo

::	FunctionInfo	= FI_Empty | FI_Function !GeneratedFunction

::	Producer	= PR_Empty
				| PR_Function !SymbIdent !Index
				| PR_Class !App ![(BoundVar, Type)] !Type
//				| PR_Constructor !SymbIdent ![Expression]
				| PR_GeneratedFunction !SymbIdent !Index
				| PR_Curried !SymbIdent

::	InstanceInfo = II_Empty | II_Node !{! Producer} !FunctionInfoPtr !InstanceInfo !InstanceInfo

::	GeneratedFunction = 
	{	gf_fun_def			:: !FunDef
	,	gf_instance_info	:: !InstanceInfo
	,	gf_cons_args		:: !ConsClasses
	,	gf_fun_index		:: !Index
	}
	
/*	... main type definitions continued .... */

::	ExpressionHeap 	:== Heap ExprInfo

::	ExprInfoPtr		:== Ptr ExprInfo

::	TempLocalVar	:== Int

::	DynamicPtr		:== ExprInfoPtr

::	ExprInfo		= EI_Empty

		/* For handling overloading */

					| EI_Overloaded !OverloadedCall 						/* initial, set by the type checker */
					| EI_Instance 	!(Global DefinedSymbol) ![Expression]	/* intermedediate, used during resolving of overloading */ 
					| EI_Selection 	![Selection] !VarInfoPtr ![Expression]	/* intermedediate, used during resolving of overloading */
					| EI_Context 	![Expression]							/* intermedediate, used during resolving of overloading */

		/* For handling dynamics */

					| EI_Dynamic 				!(Optional DynamicType) !Int
					| EI_DynamicType			!DynamicType ![DynamicPtr]

		/* Auxiliary, was EI_DynamicType before checking */

					| EI_DynamicTypeWithVars	![TypeVar] !DynamicType ![DynamicPtr]				

		/* Auxiliary, used during type checking */

					| EI_TempDynamicType 		!(Optional DynamicType) !AType ![TypeContext] !ExprInfoPtr !SymbIdent
					| EI_TempDynamicPattern 	![TypeVar] !DynamicType ![DynamicPtr] ![TempLocalVar] !AType ![TypeContext] !ExprInfoPtr !SymbIdent
					
					| EI_TypeOfDynamic 			![VarInfoPtr] !TypeCodeExpression				/* Final */
					| EI_TypeOfDynamicPattern 	![VarInfoPtr] !TypeCodeExpression				/* Final */

					| EI_TypeCode 		!TypeCodeExpression
					| EI_TypeCodes 		![TypeCodeExpression]

					| EI_Attribute !Int


		/*	EI_FreeVariables is uded to store the (free) variables occurring in the case expression */

//					| EI_FreeVariables ![UnboundVariable] !ExprInfo

		/* EI_ClassTypes is used to store the instance types of a class These type are used during fusion to generate proper types for 
		   the fusion result (i.e. the resulting function after elimination of dictionaries) */

					| EI_DictionaryType !Type
					| EI_CaseType !CaseType
					| EI_LetType ![AType]
					| EI_CaseTypeAndRefCounts !CaseType !RefCountsInCase
					| EI_LetTypeAndRefCounts ![AType] ![Int]

		/* for converting case into function patterns the following auxiliary constuctors are used */

					| EI_Default !Expression !AType !ExprInfoPtr
					| EI_DefaultFunction !SymbIdent ![Expression]
					| EI_Extended !ExtendedExprInfo !ExprInfo

::	ExtendedExprInfo
					= EEI_ActiveCase !ActiveCaseInfo

::	ActiveCaseInfo =
	{	aci_params					:: ![FreeVar]
	,	aci_opt_unfolder			:: !(Optional SymbIdent)
	,	aci_free_vars				:: !Optional [BoundVar]
	,	aci_linearity_of_patterns	:: ![[Bool]]
	}

::	RefCountsInCase = 
	{	rcc_all_variables		:: ![CountedVariable]
	,	rcc_default_variables	:: ![CountedVariable]
	,	rcc_pattern_variables	:: ![[CountedVariable]]
	}

::	CountedVariable =
	{	cv_variable	:: !VarInfoPtr
	,	cv_count	:: !Int
	}


/*
	OverloadedCall contains (type) information about functions that are overloaded. This structure is built during type checking
	and used after (standard) unification to insert the proper instances of the corresponding functions.

*/

::	OverloadedCall = 
	{	oc_symbol	:: !SymbIdent
	,	oc_context	:: ![TypeContext]
	,	oc_specials	:: ![Special]
	}

/*
	CaseType contains the type information needed to type the corresponding case construct:
		ct_pattern_type : the type of the pattern
		ct_result_type  : the type of the result (of each pattern)
		ct_cons_types   : the types of the arguments of each pattern constructor
*/
		
::	CaseType =
	{	ct_pattern_type	:: !AType
	,	ct_result_type	:: !AType
	,	ct_cons_types 	:: ![[AType]]
	}
		

::	SymbIdent =
	{	symb_name		:: !Ident
	,	symb_kind		:: !SymbKind
	,	symb_arity		:: !Int
	}

::	ConsDef =
	{	cons_symb			:: !Ident
	,	cons_type			:: !SymbolType
	,	cons_arg_vars		:: ![[ATypeVar]]
	,	cons_priority		:: !Priority
	,	cons_index			:: !Index
	,	cons_type_index		:: !Index
	,	cons_exi_vars		:: ![ATypeVar]
//	,	cons_exi_attrs		:: ![AttributeVar]
	,	cons_type_ptr		:: !VarInfoPtr
	,	cons_pos			:: !Position
	}

::	SelectorDef =
	{	sd_symb			:: !Ident
	,	sd_field		:: !Ident
	,	sd_type			:: !SymbolType
	,	sd_exi_vars		:: ![ATypeVar]
//	,	sd_exi_attrs	:: ![AttributeVar]
	,	sd_field_nr		:: !Int
	,	sd_type_index	:: !Int
	,	sd_type_ptr		:: !VarInfoPtr
	,	sd_pos			:: !Position
	}

::	SymbolType =
	{	st_vars			:: ![TypeVar]
	,	st_args			:: ![AType]
	,	st_arity		:: !Int
	,	st_result		:: !AType
	,	st_context		:: ![TypeContext]
	,	st_attr_vars	:: ![AttributeVar]
	,	st_attr_env		:: ![AttrInequality]
	}

::	TypeContext =
	{	tc_class	:: !Global DefinedSymbol
	,	tc_types	:: ![Type]
	,	tc_var		:: !VarInfoPtr
	}

::	AType =
	{	at_attribute	:: !TypeAttribute
	,	at_annotation	:: !Annotation
	,	at_type			:: !Type
	}
	
::	TempAttrId		:== Int
::	TempVarId		:== Int

::	Type	=	TA !TypeSymbIdent ![AType]
			|	(-->) infixr 9 !AType !AType
			|	(:@:) infixl 9 !ConsVariable ![AType]
			|	TB !BasicType

//			|	TFA [ATypeVar] Type

			| 	GTV !TypeVar
			| 	TV !TypeVar
			|	TempV !TempVarId				/* Auxiliary, used during type checking */

			
			|	TQV	TypeVar
			|	TempQV !TempVarId				/* Auxiliary, used during type checking */

			|	TLifted !TypeVar				/* Auxiliary, used during type checking of lifted arguments */

			|	TE

::	ConsVariable = CV 		!TypeVar
				 | TempCV 	!TempVarId
				 | TempQCV 	!TempVarId


::	DynamicType =
	{	dt_uni_vars 	:: ![ATypeVar]
	,	dt_global_vars	:: ![TypeVar]
	,	dt_type			:: !AType
	}

::	KindHeap	:== Heap KindInfo
::	KindInfoPtr	:== Ptr KindInfo

::	KindInfo	= KI_Var !KindInfoPtr
				| KI_Indirection !KindInfo
				| KI_Arrow ![KindInfo]
				| KI_Const
				
				| KI_ConsVar
				
				| KI_VarBind !KindInfoPtr
				| KI_NormVar !Int


::	TypeVarInfo  	= TVI_Empty | TVI_Type !Type | TVI_Forward !TempVarId | TVI_TypeKind !KindInfoPtr
					| TVI_SignClass !Index !SignClassification !TypeVarInfo | TVI_PropClass !Index !PropClassification !TypeVarInfo
					| TVI_Attribute TypeAttribute
					| TVI_CorrespondenceNumber !Int /* auxiliary used in module comparedefimp */
					| TVI_AType !AType /* auxiliary used in module comparedefimp */
					| TVI_Used /* to adminster that this variable is encountered (in checkOpenTypes) */
					| TVI_TypeCode !TypeCodeExpression
					| TVI_CPSLocalTypeVar !Int /* MdM - the index of the variable as generated by the theorem prover */
					| TVI_Kinds ![TypeKind] // AA: used to collect kinds during checking 
					| TVI_Kind !TypeKind
					| TVI_ConsInstance !DefinedSymbol //AA: generic cons instance function 
					| TVI_Normalized !Int /* MV - position of type variable in its definition */

::	TypeVarInfoPtr	:== Ptr TypeVarInfo
::	TypeVarHeap 	:== Heap TypeVarInfo

::	AttrVarInfo  	= AVI_Empty | AVI_Attr !TypeAttribute | AVI_Forward !TempAttrId
					| AVI_CorrespondenceNumber !Int /* auxiliary used in module comparedefimp */
					| AVI_Used
					| AVI_Count !Int /* auxiliary used in module typesupport */

::	AttrVarInfoPtr	:== Ptr AttrVarInfo
::	AttrVarHeap 	:== Heap AttrVarInfo

::	TypeHeaps =
	{	th_vars		:: ! .TypeVarHeap
	,	th_attrs	:: ! .AttrVarHeap
	}

::	TypeVar =
	{	tv_name				:: !Ident
	,	tv_info_ptr			:: !TypeVarInfoPtr
	}


::	ATypeVar =
	{	atv_attribute		:: !TypeAttribute
	,	atv_annotation		:: !Annotation
	,	atv_variable		:: !TypeVar
	}

::	TypeAttribute = TA_Unique | TA_Multi | TA_Var !AttributeVar | TA_RootVar AttributeVar | TA_TempVar !Int | TA_TempExVar
					| TA_Anonymous | TA_None
					| TA_List !Int !TypeAttribute | TA_Locked !TypeAttribute
					| TA_MultiOfPropagatingConsVar

::	AttributeVar =
	{	av_name			:: !Ident
	,	av_info_ptr		:: !AttrVarInfoPtr
	}

::	Annotation	=  AN_Strict | AN_None 

::	BasicType	= BT_Int | BT_Char | BT_Real | BT_Bool | BT_Dynamic
				| BT_File | BT_World
				| BT_String !Type /* the internal string type synonym only used to type string denotations */


::	BasicValue	= BVI !String | BVC !String | BVB !Bool | BVR !String | BVS !String


//::	TypeKind = KindVar !KindInfoPtr | KindConst | KindArrow !Int
::	TypeKind = KindVar !KindInfoPtr | KindConst | KindArrow ![TypeKind]

::	Occurrence =
	{	occ_ref_count	:: !ReferenceCount
	,	occ_bind		:: !OccurrenceBinding
	,	occ_observing	:: !Bool
	,	occ_previous 	:: ![ReferenceCount]
	}

::	ReferenceCount = RC_Used !RC_Used | RC_Unused 

::	SelectiveUse = { su_field :: !Int, su_multiply :: ![ExprInfoPtr], su_uniquely :: ![ExprInfoPtr]  }

::	RC_Used = { rcu_multiply :: ![ExprInfoPtr], rcu_selectively :: ![SelectiveUse], rcu_uniquely :: ![ExprInfoPtr] }

::	OccurrenceBinding	= OB_Empty | OB_OpenLet !Expression | OB_LockedLet !Expression
						| OB_Pattern ![(FreeVar, Int)] !OccurrenceBinding
//						| OB_Closed !LetOccurrences | OB_Marked !LetOccurrences

::	TypeDefInfo =
	{	tdi_kinds			:: ![TypeKind]
	,	tdi_properties		:: !BITVECT
	,	tdi_group			:: ![Global Index]
	,	tdi_group_nr		:: !Int
	,	tdi_group_vars		:: ![Int]
	,	tdi_cons_vars		:: ![Int]
	,	tdi_tmp_index		:: !Int
	,	tdi_classification	:: !TypeClassification
	}

::	TypeDefInfos :== {# .{# TypeDefInfo}}

::	OptGuardedAlts	= GuardedAlts ![GuardedExpr] !(Optional ExprWithLocalDefs)
				 	| UnGuardedExpr !ExprWithLocalDefs

::	GuardedExpr =
	{	alt_nodes	:: ![NodeDefWithLocals]
	,	alt_guard	:: !ParsedExpr
	,	alt_expr	:: !OptGuardedAlts
	,	alt_ident	:: !Ident
	,	alt_position:: !Position
	}

::	ExprWithLocalDefs = 
	{	ewl_nodes	:: ![NodeDefWithLocals]
	,	ewl_expr	:: !ParsedExpr
	,	ewl_locals	:: !LocalDefs
	,	ewl_position:: !Position
	}

::	NodeDefWithLocals =
	{	ndwl_strict		:: !Bool
	,	ndwl_def		:: !Bind ParsedExpr ParsedExpr
	,	ndwl_locals		:: !LocalDefs
	,	ndwl_position	:: !Position
	}


::	CaseAlt =
	{	calt_pattern	:: !ParsedExpr
	,	calt_rhs		:: !Rhs
	}
	
:: LocalDef		:== ParsedDefinition

cUniqueSelection	:== True
cNonUniqueSelection	:== False

:: ParsedExpr	= PE_List ![ParsedExpr]
				| PE_Ident !Ident
				| PE_Basic !BasicValue
				| PE_Bound !BoundExpr
				| PE_Lambda !Ident ![ParsedExpr] !ParsedExpr !Position
				| PE_Tuple ![ParsedExpr]				
				| PE_Record !ParsedExpr !(Optional Ident) ![FieldAssignment]
				| PE_ArrayPattern ![ElemAssignment]
				| PE_UpdateComprehension !ParsedExpr !ParsedExpr !ParsedExpr ![Qualifier]
				| PE_ArrayDenot ![ParsedExpr]
				| PE_Selection !Bool !ParsedExpr ![ParsedSelection]
				| PE_Update !ParsedExpr [ParsedSelection] ParsedExpr
				| PE_Case !Ident !ParsedExpr [CaseAlt]
				| PE_If !Ident !ParsedExpr !ParsedExpr !ParsedExpr
				| PE_Let !Bool !LocalDefs !ParsedExpr
				| PE_Compr !GeneratorKind !ParsedExpr ![Qualifier]
				| PE_Sequ Sequence
				| PE_WildCard
				| PE_Field !ParsedExpr !(Global FieldSymbol) /* Auxiliary, used during checking */

				| PE_ABC_Code ![String] !Bool
				| PE_Any_Code !(CodeBinding Ident) !(CodeBinding Ident) ![String]

				| PE_DynamicPattern !ParsedExpr !DynamicType
				| PE_Dynamic !ParsedExpr !(Optional DynamicType)
				
				| PE_Generic !Ident !TypeKind	/* AA: For generics, kind indexed identifier */
				
				| PE_Empty

::	ParsedSelection	= PS_Record !Ident !(Optional Ident)
					| PS_Array  !ParsedExpr
					| PS_Erroneous


::	GeneratorKind :== Bool

cIsListGenerator 	:== True
cIsArrayGenerator	:== False

:: LineAndColumn = {lc_line :: !Int, lc_column :: !Int}

::	Generator =
	{	gen_kind	:: !GeneratorKind
	,	gen_pattern :: !ParsedExpr
	,	gen_expr	:: !ParsedExpr
	,	gen_position :: !LineAndColumn
	}

::	Qualifier	=
	{	qual_generators	:: ![Generator]
	,	qual_filter		:: !Optional ParsedExpr
	,	qual_position	:: !LineAndColumn
	,	qual_filename	:: !FileName
	}

::	Sequence	= SQ_FromThen ParsedExpr ParsedExpr
				| SQ_FromThenTo ParsedExpr ParsedExpr ParsedExpr
				| SQ_From ParsedExpr
				| SQ_FromTo ParsedExpr ParsedExpr

::	BoundExpr	:== Bind ParsedExpr Ident

::	FieldAssignment :== Bind ParsedExpr Ident

::	ElemAssignment :== Bind ParsedExpr [ParsedExpr]

//::	NodeDef :== Bind ParsedExpr ParsedExpr

cIsStrict		:== True
cIsNotStrict	:== False

::	Expression	= Var !BoundVar 
				| App !App
				| (@) infixl 9  !Expression ![Expression]
				| Let !Let
				| Case !Case
				| Selection !(Optional (Global DefinedSymbol)) !Expression ![Selection]
				| Update !Expression ![Selection] Expression
				| RecordUpdate !(Global DefinedSymbol) !Expression ![Bind Expression (Global FieldSymbol)]
				| TupleSelect !DefinedSymbol !Int !Expression
//				| Lambda .[FreeVar] !Expression
				| BasicExpr !BasicValue !BasicType
				| WildCard
				| Conditional !Conditional

				| AnyCodeExpr !(CodeBinding BoundVar) !(CodeBinding FreeVar) ![String]
				| ABCCodeExpr ![String] !Bool

				| MatchExpr !(Optional (Global DefinedSymbol)) !(Global DefinedSymbol) !Expression
				| FreeVar FreeVar 
				| Constant !SymbIdent !Int !Priority !Bool	/* auxiliary clause used during checking */
				| ClassVariable !VarInfoPtr					/* auxiliary clause used during overloading */

				| DynamicExpr !DynamicExpr
//				| TypeCase !TypeCase

				| TypeCodeExpression !TypeCodeExpression
				| EE 
				| NoBind ExprInfoPtr /* auxiliary, to store fields that are not specified in a record expression */ 


::	CodeBinding	variable :== Env String variable

::	App =
	{	app_symb 		:: !SymbIdent
	,	app_args 		:: ![Expression]
	,	app_info_ptr	:: !ExprInfoPtr
	}

::	Case =
	{	case_expr		:: !Expression
	,	case_guards		:: !CasePatterns
	,	case_default	:: !Optional Expression
	,	case_ident		:: !Optional Ident
	,	case_info_ptr	:: !ExprInfoPtr
	,	case_default_pos:: !Position
	}

::	Let =
	{	let_strict_binds	:: ![LetBind]
	,	let_lazy_binds		:: ![LetBind]
	,	let_expr			:: !Expression
	,	let_info_ptr		:: !ExprInfoPtr
	,	let_expr_position	:: !Position
	}

::	LetBind =
	{	lb_dst		:: !FreeVar
	,	lb_src		:: !Expression
	,	lb_position	:: !Position
	}

::	DynamicExpr =
	{	dyn_expr		:: !Expression
	,	dyn_opt_type	:: !Optional DynamicType
	,	dyn_info_ptr	:: !ExprInfoPtr
	,	dyn_uni_vars	:: ![VarInfoPtr]			/* filled after type checking */
	,	dyn_type_code	:: !TypeCodeExpression		/* filled after type checking */
	}	

::	CasePatterns = AlgebraicPatterns !(Global Index) ![AlgebraicPattern]
				 | BasicPatterns !BasicType [BasicPattern]
				 | DynamicPatterns [DynamicPattern]						/* auxiliary */
				 | NoPattern											/* auxiliary */

::	Selection	= RecordSelection !(Global DefinedSymbol) !Int
				| ArraySelection !(Global DefinedSymbol) !ExprInfoPtr !Expression
				| DictionarySelection !BoundVar ![Selection] !ExprInfoPtr !Expression

::	TypeCodeExpression = TCE_Empty | TCE_Var !VarInfoPtr /* MV */ | TCE_TypeTerm !VarInfoPtr | TCE_Constructor !Index ![TypeCodeExpression] | TCE_Selector ![Selection] !VarInfoPtr

::	GlobalTCType = GTT_Basic !BasicType	| GTT_Constructor !TypeSymbIdent !String | GTT_Function

::	FunctionPattern	= FP_Basic !BasicValue !(Optional FreeVar)
					| FP_Algebraic !(Global DefinedSymbol) ![FunctionPattern] !(Optional FreeVar)
					| FP_Variable !FreeVar
					| FP_Dynamic ![VarInfoPtr] !FreeVar !TypeCodeExpression !(Optional FreeVar)
					| FP_Empty

::	AlgebraicPattern =
	{	ap_symbol	:: !(Global DefinedSymbol)
	,	ap_vars		:: ![FreeVar]
	,	ap_expr		:: !Expression
	,	ap_position	:: !Position
	}
	
::	BasicPattern =
	{	bp_value	:: !BasicValue
	,	bp_expr		:: !Expression
	,	bp_position	:: !Position
	}

::	TypeCase =
	{	type_case_dynamic	:: !Expression 
	,	type_case_patterns 	:: ![DynamicPattern]
	,	type_case_default	:: !Optional Expression
	,	type_case_info_ptr	:: !ExprInfoPtr
	}
	
::	DynamicPattern =
	{	dp_var					:: !FreeVar
	,	dp_type					:: !ExprInfoPtr
	,	dp_type_patterns_vars	:: ![VarInfoPtr]			/* filled after type checking */
	,	dp_type_code			:: !TypeCodeExpression		/* filled after type checking */
	,	dp_rhs					:: !Expression
	,	dp_position				:: !Position
	}
	
	
::	Conditional =
	{	if_cond		:: !Expression
	,	if_then		:: !Expression
	,	if_else		:: !Optional Expression
	}

/*
	error handling
*/

:: Position			= FunPos  FileName LineNr FunctName
					| LinePos FileName LineNr
					| PreDefPos Ident
					| NoPos

::	CoercionPosition
	=	CP_Expression !Expression
	|	CP_FunArg !Ident !Int // Function symbol, argument position (>=1)

::	IdentPos =
	{	ip_ident	:: !Ident
	,	ip_line		:: !Int
	,	ip_file		:: !FileName
	}

:: FileName			:== String

:: FunctName		:== String

:: LineNr			:== Int

cNotALineNumber :== -1

/* Used for hashing identifiers */

class needs_brackets a :: a -> Bool

instance == BoundVar
where
	(==) varid1 varid2
		= varid1.var_name == varid2.var_name

instance == Ident
where
	(==) id1 id2
		= id1.id_info == id2.id_info

instance needs_brackets AType
where
	needs_brackets {at_type}
		= needs_brackets at_type

instance needs_brackets Type
where
	needs_brackets (TA {type_arity} _)
		= type_arity > 0
	needs_brackets (_ --> _)
		= True
	needs_brackets (_ :@: _)
		= True
/*	needs_brackets (TFA _ _)
		= True
*/	needs_brackets _
		= False

instance needs_brackets Expression
where
	needs_brackets (App app)
		= app.app_symb.symb_arity > 0
	needs_brackets (_ @ _)
		= True
	needs_brackets (Let _)
		= True
	needs_brackets (Case _)
		= True
//	needs_brackets (Lambda _ _)
//		= True
	needs_brackets (Selection _ _ _)
		= True
	needs_brackets _
		= False

instance needs_brackets a
where
	needs_brackets _ = False

instance <<< BasicType
where
	(<<<) file BT_Int			= file <<< "Int"
	(<<<) file BT_Char			= file <<< "Char"
	(<<<) file BT_Real			= file <<< "Real"
	(<<<) file BT_Bool			= file <<< "Bool"
/*	(<<<) file (BT_String _)	= file <<< "String" */
	(<<<) file BT_Dynamic		= file <<< "Dynamic"
	(<<<) file BT_File			= file <<< "File"
	(<<<) file BT_World			= file <<< "World"

instance <<< TypeVar
where
//	(<<<) file varid = file <<< varid.tv_name 
	(<<<) file varid = file <<< varid.tv_name <<< "<" <<< ptrToInt (varid.tv_info_ptr) <<< ">"

instance <<< AttributeVar
where
//	(<<<) file {av_name,av_info_ptr} = file <<< av_name <<< "[" <<< ptrToInt av_info_ptr <<< "]"
	(<<<) file {av_name,av_info_ptr} = file <<< av_name

instance toString AttributeVar
where
//	toString {av_name,av_info_ptr} = toString av_name + "[" + toString (ptrToInt av_info_ptr) + "]"
	toString {av_name,av_info_ptr} = toString av_name

instance <<< AType
where
	(<<<) file {at_annotation,at_attribute,at_type}
		= file <<< at_annotation <<< at_attribute <<< at_type

instance <<< TypeAttribute
where
	(<<<) file ta
		= file <<< toString ta

instance toString TypeAttribute
where
	toString (TA_Unique)
		= "*"
	toString (TA_TempVar tav_number)
		= "u" + toString tav_number + ":"
	toString (TA_Var avar)
		= toString avar + ":"
	toString (TA_RootVar avar)
		= toString avar + ":"
	toString (TA_Anonymous)
		= "."
	toString TA_None
		= ""
	toString TA_Multi
		= "o "
	toString TA_MultiOfPropagatingConsVar
		= "@@ "
	toString (TA_List _ _)
		= "??? "
	toString TA_TempExVar
		= PA_BUG "(E)" (abort "toString TA_TempExVar")

instance <<< Annotation
where
	(<<<) file an = file <<< toString an

instance toString Annotation
where
	toString AN_Strict	= "!" 
	toString _			= "" 

instance <<< ATypeVar
where
	(<<<) file {atv_annotation,atv_attribute,atv_variable}
		= file <<< atv_annotation <<< atv_attribute <<< atv_variable

instance <<< ConsVariable
where
	(<<<) file (CV tv)
		= file <<< tv
	(<<<) file (TempCV tv)
		= file <<<  "v" <<< tv <<< ' ' 
	(<<<) file (TempQCV tv)
		= file <<<  "E." <<< tv <<< ' ' 

instance <<< Type
where
	(<<<) file (TV varid)
		= file <<< varid
	(<<<) file (TempV tv_number)
		= file  <<< 'v' <<< tv_number <<< ' ' 
	(<<<) file (TA consid types)
		= file  <<< consid <<< " " <<< types
	(<<<) file (arg_type --> res_type)
		= file <<< arg_type <<< " -> " <<< res_type
	(<<<) file (type :@: types)
		= file <<< type <<< " @" <<< types
	(<<<) file (TB tb)
		= file <<< tb
/*	(<<<) file (TFA vars types)
		= file <<< "A." <<< vars <<< ':' <<< types
*/	(<<<) file (TQV varid)
		= file <<< "E." <<< varid
	(<<<) file (TempQV tv_number)
		= file  <<< "E." <<< tv_number <<< ' ' 
	(<<<) file TE
		= file <<< "### EMPTY ###"
/*
instance <<< [a] | <<< , needs_brackets a
where
	(<<<) file [] 		= file
	(<<<) file [x:xs]
		| needs_brackets x
			= file <<< " (" <<< x <<< ')' <<< xs
			= file <<< ' ' <<< x <<< xs
*/

instance <<< SymbolType
where
	(<<<) file st=:{st_vars,st_attr_vars}
		| st.st_arity == 0
			= write_inequalities st.st_attr_env (write_contexts st.st_context (file <<< '[' <<< st_vars <<< ',' <<< st_attr_vars <<< ']' <<< st.st_result))
			= write_inequalities st.st_attr_env (write_contexts st.st_context (file <<< '[' <<< st_vars <<< ',' <<< st_attr_vars <<< ']' <<< st.st_args <<< " -> " <<< st.st_result))

write_contexts [] file
	= file
write_contexts [tc : tcs] file
	= write_contexts2 tcs (file <<< " | " <<< tc) 
where
	write_contexts2 [] file
		= file
	write_contexts2 [tc : tcs] file
		= write_contexts2 tcs (file <<< " & " <<< tc)

instance <<< AttrInequality
where
	(<<<) file {ai_demanded,ai_offered}
		= file <<< ai_offered <<< " <= " <<< ai_demanded
	
write_inequalities [] file
	= file
write_inequalities [ineq:ineqs] file
	= write_remaining_inequalities ineqs (file <<< ',' <<< ineq)
where
	write_remaining_inequalities [] file
		= file
	write_remaining_inequalities [ineq:ineqs] file
		= write_remaining_inequalities ineqs (file <<< ' ' <<< ineq)

instance <<< TypeContext
where
	(<<<) file co = file <<< co.tc_class <<< " " <<< co.tc_types <<< " <" <<< ptrToInt co.tc_var <<< '>'

instance <<< SymbIdent
where
	(<<<) file symb=:{symb_kind = SK_Function symb_index }
		= file <<< symb.symb_name <<<  '@' <<< symb_index
	(<<<) file symb=:{symb_kind = SK_LocalMacroFunction symb_index }
		= file <<< symb.symb_name <<<  '@' <<< symb_index
	(<<<) file symb=:{symb_kind = SK_GeneratedFunction _ symb_index }
		= file <<< symb.symb_name <<<  '@' <<< symb_index
	(<<<) file symb=:{symb_kind = SK_OverloadedFunction symb_index }
		= file <<< symb.symb_name <<<  "[o]@" <<< symb_index
	(<<<) file symb
		= file <<< symb.symb_name 

instance <<< TypeSymbIdent
where
	(<<<) file symb	= file <<< symb.type_name <<< '.' <<< symb.type_index

instance <<< ClassSymbIdent
where
	(<<<) file symb	= file <<< symb.cs_name 

instance <<< BoundVar
where
	(<<<) file {var_name,var_info_ptr,var_expr_ptr}
		= file <<< var_name <<< '<' <<< ptrToInt var_info_ptr <<< '>'

instance <<< (Bind a b) | <<< a & <<< b 
where
	(<<<) file {bind_src,bind_dst} = file <<< bind_dst <<<  " = " <<< bind_src 


instance <<< AlgebraicPattern
where
	(<<<) file g = file <<< g.ap_symbol <<< g.ap_vars <<< " -> " <<< g.ap_expr

instance <<< BasicPattern
where
	(<<<) file g = file <<< g.bp_value <<< " -> " <<< g.bp_expr

instance <<< CasePatterns
where
	(<<<) file (BasicPatterns type patterns) = file <<< " " <<<patterns
	(<<<) file (AlgebraicPatterns type patterns) = file <<< patterns
	(<<<) file (DynamicPatterns patterns) = file <<< patterns
	(<<<) file NoPattern = file 

instance <<< CheckedAlternative
where
	(<<<) file {ca_rhs} = file <<< ca_rhs

instance <<< Qualifier
where
	(<<<) file {qual_generators,qual_filter = Yes qual_filter} = file <<< qual_generators <<< "| " <<< qual_filter
	(<<<) file {qual_generators,qual_filter = No} = file <<< qual_generators

instance <<< Generator
where
	(<<<) file {gen_kind,gen_pattern,gen_expr}
		= file <<< gen_pattern <<< (if gen_kind "<-" "<-:") <<< gen_expr

instance <<< BasicValue
where
	(<<<) file (BVI int)	= file <<< int
	(<<<) file (BVC char)	= file <<< char
	(<<<) file (BVB bool)	= file <<< bool
	(<<<) file (BVR real)	= file <<< real
	(<<<) file (BVS string)	= file <<< string
	
instance <<< Sequence
where
	(<<<) file (SQ_From expr) = file <<< expr
	(<<<) file (SQ_FromTo from_expr to_expr) = file <<< from_expr <<< ".."  <<< to_expr
	(<<<) file (SQ_FromThen from_expr then_expr) = file <<< from_expr  <<< ',' <<< then_expr <<< ".."
	(<<<) file (SQ_FromThenTo from_expr then_expr to_expr) = file <<< from_expr  <<< ',' <<< then_expr <<< ".." <<< to_expr

instance <<< Expression
where
	(<<<) file (Var ident) = file <<< ident
	(<<<) file (App {app_symb, app_args, app_info_ptr})
		= file <<< app_symb <<< ' ' <<< app_args
	(<<<) file (f_exp @ a_exp) = file <<< '(' <<< f_exp <<< " @ " <<< a_exp <<< ')'
	(<<<) file (Let {let_info_ptr, let_strict_binds, let_lazy_binds, let_expr}) 
			= write_binds "" (write_binds "!" (file <<< "let" <<< '\n') let_strict_binds) let_lazy_binds <<< "in\n" <<< let_expr
	where
		write_binds x file []
			= file
		write_binds x file [bind : binds]
			= write_binds x (file <<< x <<< " " <<< bind <<< '\n') binds
 	(<<<) file (Case {case_expr,case_guards,case_default=No})
		= file <<< "case " <<< case_expr <<< " of\n" <<< case_guards
	(<<<) file (Case {case_expr,case_guards,case_default= Yes def_expr})
		= file <<< "case " <<< case_expr <<< " of\n" <<< case_guards <<< "\n\t->" <<< def_expr
	(<<<) file (BasicExpr basic_value basic_type) = file <<< basic_value
	(<<<) file (Conditional {if_cond,if_then,if_else}) =
			else_part (file <<< "IF " <<< if_cond <<< "\nTHEN\n" <<< if_then) if_else
	where
		else_part file No = file <<< '\n'
		else_part file (Yes else) = file <<< "\nELSE\n" <<< else <<< '\n'

/*	(<<<) file (Conditional {if_cond = {con_positive,con_expression},if_then,if_else}) =
			else_part (file <<< (if con_positive "IF " "IFNOT ") <<< con_expression <<< "\nTHEN\n" <<< if_then) if_else
	where
		else_part file No = file <<< '\n'
		else_part file (Yes else) = file <<< "\nELSE\n" <<< else <<< '\n'
*/
 	(<<<) file (Selection opt_tuple expr selectors) = file <<< expr <<< selector_kind opt_tuple <<< selectors
	where
		selector_kind No		= '.'
		selector_kind (Yes _)	= '!'
	(<<<) file (Update expr1 selections expr2) =  file <<< '{' <<< expr1  <<< " & " <<<  selections <<< " = " <<< expr2 <<< '}'
	(<<<) file (RecordUpdate cons_symbol expression expressions) = file <<< '{' <<< cons_symbol <<< ' ' <<< expression <<< " & " <<< expressions <<< '}'
	(<<<) file (TupleSelect field field_nr expr) = file <<< expr <<<'.' <<< field_nr
//	(<<<) file (Lambda vars expr) = file <<< '\\' <<< vars <<< " -> " <<< expr
	(<<<) file WildCard = file <<< '_'
	(<<<) file (MatchExpr _ cons expr) = file <<< cons <<< " =: " <<< expr
	(<<<) file EE = file <<< "** E **"
	(<<<) file (NoBind _) = file <<< "** NB **"
	(<<<) file (DynamicExpr {dyn_expr,dyn_uni_vars,dyn_type_code})     = writeVarPtrs (file <<< "dynamic " <<< dyn_expr <<< " :: dyn_uni_vars") dyn_uni_vars <<< "dyn_type_code=" <<< dyn_type_code 
//	(<<<) file (TypeCase type_case)      = file <<< type_case
	(<<<) file (TypeCodeExpression type_code)      = file <<< type_code
	(<<<) file (Constant symb _ _ _)         = file <<<  "** Constant **" <<< symb

	(<<<) file (ABCCodeExpr code_sequence do_inline)      = file <<< (if do_inline "code inline\n" "code\n") <<< code_sequence
	(<<<) file (AnyCodeExpr input output code_sequence)   = file <<< "code\n" <<< input <<< "\n" <<< output <<< "\n" <<< code_sequence

	(<<<) file (FreeVar {fv_name})         	= file <<< fv_name
	(<<<) file (ClassVariable info_ptr)         	= file <<< "ClassVariable " <<< ptrToInt info_ptr

	(<<<) file expr         				= abort ("<<< (Expression) [line 1290]" )//<<- expr)
	
instance <<< LetBind
where
	(<<<) file {lb_dst, lb_src}
		= file <<< lb_dst <<< " = " <<< lb_src <<< "\n"

instance <<< TypeCase
where
	(<<<) file {type_case_dynamic,type_case_patterns,type_case_default}
			= file <<< "typecase " <<< type_case_dynamic <<< "of\n" <<<
				type_case_patterns <<< type_case_default

instance <<< DynamicPattern
where
	(<<<) file {dp_type_patterns_vars,dp_var,dp_rhs,dp_type_code}
			= writeVarPtrs (file <<< dp_var <<< " :: ")  dp_type_patterns_vars <<<  dp_type_code <<< " = " <<< dp_rhs

writeVarPtrs file []
	= file
writeVarPtrs file vars
	= write_var_ptrs (file <<< '<') vars <<< '>'
	where
		write_var_ptrs file [var]
			= file <<< ptrToInt var
		write_var_ptrs file [var : vars]
			= write_var_ptrs (file <<< ptrToInt var <<< '.') vars
		
		
instance <<< TypeCodeExpression
where
	(<<<) file TCE_Empty
		= file
	(<<<) file (TCE_Var info_ptr)
		= file <<< "TCE_Var " <<<