org.jscience.computing.ai.planning
Class Term

java.lang.Object
  org.jscience.computing.ai.planning.CompileTimeObject
      org.jscience.computing.ai.planning.Term

Direct Known Subclasses:

TermCall, TermConstant, TermList, TermNumber, TermVariable

public abstract class Term
extends CompileTimeObject

Each term, both at compile time and at run time, is an instance of a class derived from this abstract class.

Constructor Summary

Term()

Method Summary

abstract Term	bind(Term[] binding) To apply a given binding to this term.
abstract boolean	equals(Term t) Whether or not another term is equivalent to this term.
abstract boolean	findUnifier(Term t, Term[] binding) To find a unifier that binds this term to another given term.
abstract boolean	isGround() Is this term ground (i.e., has no variables)?
boolean	isNil() Is this a NIL term?
static Term[]	merge(Term[][] inp, int howMany) This function is used to merge an arbitrary number of bindings.
static void	merge(Term[] inp1, Term[] inp2) This function is used to merge two bindings.
void	print() This function is used to print the value of this term.
abstract java.lang.String	toString() This function is used to produce a printable String showing the value of this term.

Methods inherited from class org.jscience.computing.ai.planning.CompileTimeObject

toCode

Methods inherited from class java.lang.Object

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

Constructor Detail

Term

public Term()

Method Detail

bind

public abstract Term bind(Term[] binding)

To apply a given binding to this term.

Parameters:

binding - an array of terms, indexed by the integers associated with variable symbols.

Returns:

the result of binding.

equals

public abstract boolean equals(Term t)

Whether or not another term is equivalent to this term.

Parameters:

t - the term being compared to this term.

Returns:

true if the two terms are equal, false otherwise.

findUnifier

public abstract boolean findUnifier(Term t,
                                    Term[] binding)

To find a unifier that binds this term to another given term.

Parameters:

t - the term with which we are finding a unifier.

binding - the unifier to be returned.

Returns:

false if the two terms can not be unified, true otherwise.

isGround

public abstract boolean isGround()

Is this term ground (i.e., has no variables)?

Returns:

true if this term is ground, false otherwise.

isNil

public boolean isNil()

Is this a NIL term?

Returns:

true if this is a NIL term, false otherwise.

merge

public static void merge(Term[] inp1,
                         Term[] inp2)

This function is used to merge two bindings. Bindings are represented as an array of terms, each element showing what its corresponding variable should be mapped to.

Parameters:

inp1 - the first binding, also the result of merging.

inp2 - the second binding.

merge

public static Term[] merge(Term[][] inp,
                           int howMany)

This function is used to merge an arbitrary number of bindings.

Parameters:

inp - the bindings to be merged. This is a two dimensional array, the first dimension indexes the different bindings, and the second dimension indexes variables within each binding.

howMany - how many of available bindings we want to merge. Bindings indexed 0 to howMany-1 are merged.

Returns:

the result of merging.

print

public void print()

This function is used to print the value of this term.

toString

public abstract java.lang.String toString()

This function is used to produce a printable String showing the value of this term.

Overrides:

toString in class java.lang.Object

Returns:

the printable String that shows the value of this term.