uk.ac.man.cs.rainbow.rapa.data
Class Expression

java.lang.Object
  |
  +--uk.ac.man.cs.rainbow.rapa.data.Expression

All Implemented Interfaces:

Argument, Serializable, Value, VariableContainer

Direct Known Subclasses:

Application, Bool, Constant, Data, Number, Register, TupleExpression, Variable

public abstract class Expression

extends Object

implements Serializable, Value

Implementations of some methods for values in RAPA and GCL.

See Also:

Serialized Form

Constructor Summary

Expression()

Method Summary

abstract Value	apply(Unifier u) Apply a unifier to this value to get a new value.
void	compatableWith(Argument arg) Check that this value is compatable with the argument.
boolean	equals(Object o)
abstract boolean	equals(Value val)
ValueWhite[]	evaluate(Map funcs, Map regs, HashMap whiteboard) Evaluate the expression/value under the given substitution over functions and valuation of register contents.
Type	getNodeType()
abstract Type	getResultType()
abstract boolean	occurs(Substitution s, Variable v) Check whether the variable occurs in this value under the given substitution.
Value	subst(GeneralSubstitution s) Apply a substitution to this value to get a new value.
abstract Value	subst(Substitution s) Apply a substitution to this value to get a new value.
abstract Substitution	unify(Substitution s, Value val) Get the substitution which unifies this value with the given value, after applying the given substitution.

Methods inherited from class java.lang.Object

clone, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface uk.ac.man.cs.rainbow.rapa.data.VariableContainer

hasVariable

Constructor Detail

Expression

public Expression()

Method Detail

apply

public abstract Value apply(Unifier u)

Description copied from interface: Value

Apply a unifier to this value to get a new value.

Specified by:

apply in interface Value

subst

public abstract Value subst(Substitution s)

Description copied from interface: Value

Apply a substitution to this value to get a new value.

Specified by:

subst in interface Value

occurs

public abstract boolean occurs(Substitution s,
                               Variable v)

Description copied from interface: Value

Check whether the variable occurs in this value under the given substitution.

Specified by:

occurs in interface Value

unify

public abstract Substitution unify(Substitution s,
                                   Value val)
                            throws NotUnifiable

Description copied from interface: Value

Get the substitution which unifies this value with the given value, after applying the given substitution.

Specified by:

unify in interface Value

Following copied from interface: uk.ac.man.cs.rainbow.rapa.data.Value

Parameters:

subst - The substitution to apply first.

val - The value to unify with this value.

Returns:

The substitution that is the combination of the given substitution and whatever extra substitutions are necessary to unify the two values.

Throws:

NotUnifiable - If the two values cannot be unified.

equals

public abstract boolean equals(Value val)

compatableWith

public void compatableWith(Argument arg)

Description copied from interface: Value

Check that this value is compatable with the argument.

Specified by:

compatableWith in interface Value

Following copied from interface: uk.ac.man.cs.rainbow.rapa.data.Value

See Also:

GeneralSubstitution

subst

public Value subst(GeneralSubstitution s)

Description copied from interface: Value

Apply a substitution to this value to get a new value.

Specified by:

subst in interface Value

equals

public boolean equals(Object o)

Overrides:

equals in class Object

getResultType

public abstract Type getResultType()

getNodeType

public Type getNodeType()

evaluate

public ValueWhite[] evaluate(Map funcs,
                             Map regs,
                             HashMap whiteboard)

Description copied from interface: Value

Evaluate the expression/value under the given substitution over functions and valuation of register contents. May return multiple values if there are several possible valuations of the given expression.

Specified by:

evaluate in interface Value