prolog.implementation
Class Variable

java.lang.Object
  |
  +--prolog.implementation.Variable

All Implemented Interfaces:

IAtom

public class Variable

extends java.lang.Object

implements IAtom

This class encapsulates a variable value used in queries. Because all names in the coder's program are replaced by integers, the internal representation of a atom is a integer value. This integer value can be decoded using the symboltable generated by the parser. A value can be compared with a filled cell in a database table row

prolog: myFact(dan,X).

in this example, a atom would be "X" a variable

Field Summary

protected int

name the interpreter internal representation of the variable. this is the index for the symboltable.

Constructor Summary

Variable(int name)
creates a new Variable

Method Summary

boolean	equals(java.lang.Object o) !!!
int	getName() the key in symboltable of the name
java.lang.String	toString() returns a string representation of the atom.
java.lang.String	toString(ISymbolTable table) returns a string representation of the atom. because all names of the programmer's programm are replaced by integers, this function requires the additional stringtable to decode the integers into strings again.

Methods inherited from class java.lang.Object

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

Field Detail

name

protected int name

the interpreter internal representation of the variable. this is the index for the symboltable.

Constructor Detail

Variable

public Variable(int name)

creates a new Variable

Parameters:

name - is the name ;-)

Method Detail

getName

public int getName()

the key in symboltable of the name

Specified by:

getName in interface IAtom

equals

public boolean equals(java.lang.Object o)

!!! a variable is equal to anything !!!

Overrides:

equals in class java.lang.Object

Returns:

allways true !!!

toString

public java.lang.String toString()

returns a string representation of the atom.

Overrides:

toString in class java.lang.Object

toString

public java.lang.String toString(ISymbolTable table)

returns a string representation of the atom. because all names of the programmer's programm are replaced by integers, this function requires the additional stringtable to decode the integers into strings again.

Specified by:

toString in interface IAtom