Unifier

java.lang.Object

edu.uky.ai.lp.logic.Unifier

All Implemented Interfaces:: java.lang.Cloneable

public class Unifier
extends java.lang.Object
implements java.lang.Cloneable

A unifier tracks which variable are equal to one another and which variable are equal to constants.

Author:: Stephen G. Ware

Constructor Summary

Constructors

Constructor Description

Unifier()
Constructs an empty unifier.

Method Summary

Modifier and Type	Method	Description
`Unifier`	`clone()`
`Term`	`get(Variable variable)`	Returns the value assigned to a variable (if any) under this unifier.
`Unifier`	`set(Variable variable, Term value)`	Sets a variable equal to a value (if value is a constant) or as having the same value as another variable (if value is a variable).
`java.lang.String`	`toString()`

Methods inherited from class java.lang.Object

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

Constructor Details
- Unifier
  
  public Unifier()
  
  Constructs an empty unifier.
Method Details
- toString
  
  public java.lang.String toString()
  
  Overrides:
  
  toString in class java.lang.Object
- clone
  
  public Unifier clone()
  
  Overrides:
  
  clone in class java.lang.Object
- get
  
  public Term get(Variable variable)
  
  Returns the value assigned to a variable (if any) under this unifier.
  
  Parameters:
  
  variable - the variable
  
  Returns:
  
  the value assigned to the variable (if any)
- set
  
  public Unifier set(Variable variable, Term value)
  
  Sets a variable equal to a value (if value is a constant) or as having the same value as another variable (if value is a variable). Note that this object is not modified; a new unifier is returned.
  
  Parameters:
  
  variable - the variable to set
  
  value - the value to set it to
  
  Returns:
  
  the resulting unifier, or null if the variable cannot be set to that value