hlt.language.design.types

Class TypeParameter

java.lang.Object

hlt.language.design.types.Type

hlt.language.design.types.StaticType

hlt.language.design.types.TypeParameter

All Implemented Interfaces:

Bindable, Valuable

public class TypeParameter
extends StaticType
implements Bindable

Field Summary

Fields inherited from class hlt.language.design.types.Type

ARRAY, BAG, BOOLEAN, BOXABLE, CHAR, CLASS, COLLECTION, CONSTANT, DEFINED, FUNCTION, INT, INT_RANGE, INT_SORT, LIST, NAMED_TUPLE, OBJECT_SORT, PARAMETER, REAL, REAL_RANGE, REAL_SORT, SET, STRING, TUPLE, VOID, VOID_SORT

Constructor Summary

Constructors

Constructor and Description
TypeParameter()

Method Summary

Methods

Modifier and Type	Method and Description
boolean	addResiduation(ResiduatedGoal residuation, int refCount) Installs the specified residuation to be triggered by this type parameter, saving the specified reference count to reinstate for the residuation upon unbinding this type parameter.
boolean	bind(Valuable value) Binds this bindable to the given valuable.
boolean	bind(Valuable valuable, GoalProver prover) Binds this type parameter to the given valuable in the context of the given prover.
void	checkOccurrence(TypeParameter parameter, Type context, TypeChecker typeChecker) Throws a FailedUnificationException if the specified type parameter occurs in this type.
Type	copy() This returns this type parameter unchanged.
Type	copy(java.util.HashMap parameters) Returns a copy of this TypeParameter as per the renaming given by the specified HashMap.
void	curry(int depth, TypeChecker typeChecker) If this this a function type, transforms the type by splitting the domains at the specified depth, and records the old form in the appropriate trail of the specified type-checker for undoing purposes.
int	eqCode() Returns a hash code for this type - the reason for using the name eqCode (rather than overriding hashCode), is that it is important to preserve the implementation of java.lang.Object.hashCode for type parameters (to be compatible with ==).
boolean	equals(java.lang.Object object) Returns true iff this type parameter is the given object.
Type	findValue() This returns the type value this is bound to and side-effects the binding chains by shortening them (i.e., like the FIND operation of the "UNION/FIND" algorithm.
Type	flatten() Flattens this type parameter's value by uncurrying all the domains of all function types that occur in it.
java.util.HashSet	getParameters(java.util.HashSet set) Returns the specified set augmented with all the unbound type parameters that occur in this type.
Type	instantiate(java.util.HashMap substitution) Returns the instance value given for this TypeParameter by the specified substitution, or this if none is given.
boolean	isBound() Returns true iff this bindable is bound.
boolean	isEqualTo(Type type) Returns true iff this type parameter is the given one.
boolean	isEqualTo(Type type, java.util.HashMap parameters) Returns true iff this type is parameter is equal to the given one under the renaming of type parameters specified by the given HashMap.
boolean	isPolymorphic()
boolean	isUnbound() Returns true iff this bindable is unbound.
byte	kind() This returns the value identifying what kind of type this is.
int	numberOfTypeComponents() Returns the number of type components making up this type.
int	parameterIndex() This returns this parameter's index in the header array of a type's quantifies string where this appears.
ObjectToIntMap	residuations()
void	setTypeRefComponent(int n, Type type) Sets the n-th undereferenced type component of this type to the specified type; throws a NoSuchTypeComponentException otherwise.
java.lang.String	toString()
Type	typeRefComponent(int n) Returns the n-th undereferenced type component in this type, if any; throws a NoSuchTypeComponentException otherwise.
void	unbind() This unbinds this type parameter and resets the reference counts for all residuations this has a trigger link with, if any.
boolean	unify(Type type) NB: does not perform the "occurs-check" test.
void	unify(Type type, TypeChecker typeChecker) Unifies this type parameter with the given type in the context of the given type-checker.
Type	value() This method acts as a type parameter dereferencing for possibly bound type parameters.

Methods inherited from class hlt.language.design.types.Type

actualType, array, array, baseType, baseTypeRef, BOOLEAN, BOXED_BOOLEAN, BOXED_CHAR, BOXED_INT, BOXED_REAL, boxSort, CHAR, getParameters, getValue, INT, is, isBag, isBoolean, isBoxedType, isChar, isCollection, isGlobalUnsafe, isInt, isList, isPrimitive, isReal, isSet, isString, isVoid, kindString, rank, REAL, resetNames, setBoxed, shadowType, sort, standardize, toFullString, toQuantifiedString, toQuantifiedString, typeComponent, unwrapper, wrapper

Methods inherited from class java.lang.Object

getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface hlt.language.design.types.Valuable

getValue

Constructor Detail

TypeParameter

public TypeParameter()

Method Detail

residuations

public final ObjectToIntMap residuations()

numberOfTypeComponents

public final int numberOfTypeComponents()

Description copied from class: Type

Returns the number of type components making up this type.

Specified by:

numberOfTypeComponents in class Type

typeRefComponent

public final Type typeRefComponent(int n)
                            throws NoSuchTypeComponentException

Description copied from class: Type

Returns the n-th undereferenced type component in this type, if any; throws a NoSuchTypeComponentException otherwise.

Specified by:

typeRefComponent in class Type

Throws:

NoSuchTypeComponentException

setTypeRefComponent

public final void setTypeRefComponent(int n,
                       Type type)
                               throws NoSuchTypeComponentException

Description copied from class: Type

Sets the n-th undereferenced type component of this type to the specified type; throws a NoSuchTypeComponentException otherwise.

Specified by:

setTypeRefComponent in class Type

Throws:

NoSuchTypeComponentException

kind

public final byte kind()

Description copied from class: Type

This returns the value identifying what kind of type this is.

Specified by:

kind in class Type

value

public final Type value()

This method acts as a type parameter dereferencing for possibly bound type parameters. Type parameters act as logical variable in Prolog and may get bound by type unification during type checking/inference.

Overrides:

value in class Type

findValue

public final Type findValue()

This returns the type value this is bound to and side-effects the binding chains by shortening them (i.e., like the FIND operation of the "UNION/FIND" algorithm. In other words, it returns the same value as the value() method, but with a side-effect of setting its _value field to the type it is bound to (which is itself if unbound)

Overrides:

findValue in class Type

isBound

public final boolean isBound()

Description copied from interface: Bindable

Returns true iff this bindable is bound.

Specified by:

isBound in interface Bindable

isUnbound

public final boolean isUnbound()

Description copied from interface: Bindable

Returns true iff this bindable is unbound.

Specified by:

isUnbound in interface Bindable

bind

public final boolean bind(Valuable valuable,
           GoalProver prover)

Binds this type parameter to the given valuable in the context of the given prover. This binding is appropriately trailed in the contextual prover for undoing purposes. Returns true.

Specified by:

bind in interface Bindable

bind

public final boolean bind(Valuable value)

Description copied from interface: Bindable

Binds this bindable to the given valuable.

Specified by:

bind in interface Bindable

unbind

public final void unbind()

This unbinds this type parameter and resets the reference counts for all residuations this has a trigger link with, if any.

Specified by:

unbind in interface Bindable

addResiduation

public final boolean addResiduation(ResiduatedGoal residuation,
                     int refCount)

Installs the specified residuation to be triggered by this type parameter, saving the specified reference count to reinstate for the residuation upon unbinding this type parameter.

getParameters

public final java.util.HashSet getParameters(java.util.HashSet set)

Description copied from class: Type

Returns the specified set augmented with all the unbound type parameters that occur in this type.

Overrides:

getParameters in class Type

isPolymorphic

public final boolean isPolymorphic()

Overrides:

isPolymorphic in class Type

curry

public final void curry(int depth,
         TypeChecker typeChecker)

Description copied from class: Type

If this this a function type, transforms the type by splitting the domains at the specified depth, and records the old form in the appropriate trail of the specified type-checker for undoing purposes. For example, currying A[1],...,A[n]n -> A at depth k (A[k+1],...,A[n] -> A). If this type is a type parameter, this will curry its value if any. Otherwise, does nothing.

N.B.: The following definition specifies only the default behavior for this method. Specific subclasses are generally expected to override this method.

Overrides:

curry in class Type

flatten

public final Type flatten()

Flattens this type parameter's value by uncurrying all the domains of all function types that occur in it. This is the canonical for used for all types of defined symbols.

Overrides:

flatten in class Type

parameterIndex

public final int parameterIndex()

This returns this parameter's index in the header array of a type's quantifies string where this appears.

copy

public final Type copy(java.util.HashMap parameters)

Returns a copy of this TypeParameter as per the renaming given by the specified HashMap. If this TypeParameter is already renamed by the parameters, then the renamed copy is returned. Otherwise, a fresh TypeParameter is entered as a renaming for it in the parameters and returned.

Overrides:

copy in class Type

instantiate

public final Type instantiate(java.util.HashMap substitution)

Returns the instance value given for this TypeParameter by the specified substitution, or this if none is given.

Overrides:

instantiate in class Type

copy

public final Type copy()

This returns this type parameter unchanged. Note the difference of this method and its namesake copy(HashMap) taking a renaming table, and which returns a distinct copy. This difference is very important as an unquantified TypeParameter must be regarded as a constant type that may be shared in a context. In the absence of this context (provided by a renaming table in the method copy(HashMap)), it must be assumed that the renaming is the identity to capture consistently several occurrences.

Overrides:

copy in class Type

unify

public final void unify(Type type,
         TypeChecker typeChecker)
                 throws FailedUnificationException

Unifies this type parameter with the given type in the context of the given type-checker. If this occurs in the specified type, unification fails by throwing a FailedUnificationException. Otherwise this get bound to the specified type. This binding is appropriately trailed in the contextual type-checker for undoing purposes.

Specified by:

unify in class Type

Throws:

FailedUnificationException

unify

public final boolean unify(Type type)

NB: does not perform the "occurs-check" test.

Specified by:

unify in class Type

checkOccurrence

public final void checkOccurrence(TypeParameter parameter,
                   Type context,
                   TypeChecker typeChecker)
                           throws FailedUnificationException

Description copied from class: Type

Throws a FailedUnificationException if the specified type parameter occurs in this type. The type context is the outermost type enclosing this.

N.B.: The following definition specifies only the default behavior for this method. Specific subclasses are generally expected to override this method.

Overrides:

checkOccurrence in class Type

Throws:

FailedUnificationException

eqCode

public final int eqCode()

Description copied from class: Type

Returns a hash code for this type - the reason for using the name eqCode (rather than overriding hashCode), is that it is important to preserve the implementation of java.lang.Object.hashCode for type parameters (to be compatible with ==). All we require with this new code is that it be compatible with type equality as defined by isEqualTo - and it is! Incidentally, the same reason goes for preserving equals for type parameters to be compatible with == - and it is (see TypeParameter).

Specified by:

eqCode in class Type

equals

public final boolean equals(java.lang.Object object)

Returns true iff this type parameter is the given object.

Overrides:

equals in class Type

isEqualTo

public final boolean isEqualTo(Type type)

Returns true iff this type parameter is the given one.

Specified by:

isEqualTo in class Type

isEqualTo

public final boolean isEqualTo(Type type,
                java.util.HashMap parameters)

Returns true iff this type is parameter is equal to the given one under the renaming of type parameters specified by the given HashMap.

Specified by:

isEqualTo in class Type

toString

public final java.lang.String toString()

Overrides:

toString in class java.lang.Object