standup.unify
Class Unification

java.lang.Object
  standup.unify.Unification

public class Unification
extends Object

A class that provides static methods for performing unification of two Unifiable objects.

Author:

Ruli Manurung

Field Summary

(package private) static int

FAIL

Constructor Summary

Unification()

Method Summary

static boolean	isVariableString(String obj)
private static boolean	occurCheck(UnifiableVariable v, Unifiable x)
static Bindings	unify(Unifiable x, Unifiable y) Unifies x and y and returns the resulting Bindings.
static Bindings	unify(Unifiable x, Unifiable y, Bindings b) Unifies x and y using the bindings built so far in b, and returns the resulting Bindings.
private static Bindings	unifyVar(UnifiableVariable v, Unifiable x, Bindings b)

Methods inherited from class java.lang.Object

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

Field Detail

FAIL

static final int FAIL

See Also:

Constant Field Values

Constructor Detail

Unification

public Unification()

Method Detail

unify

public static Bindings unify(Unifiable x,
                             Unifiable y)

Unifies x and y and returns the resulting Bindings. The unification is non-destructive, in the sense that x and y are unmodified. Use Bindings.dereference(Unifiable) to obtain the 'destructively' unified objects.

Parameters:

x - first Unifiable object to be unified

y - second Unifiable object to be unified

Returns:

the resulting Bindings of the unification

unify

public static Bindings unify(Unifiable x,
                             Unifiable y,
                             Bindings b)

Unifies x and y using the bindings built so far in b, and returns the resulting Bindings. The bindings in b are unmodified.

Parameters:

x - first Unifiable object to be unified

y - second Unifiable object to be unified

b - the bindings built so far

Returns:

the resulting Bindings of the unification

unifyVar

private static Bindings unifyVar(UnifiableVariable v,
                                 Unifiable x,
                                 Bindings b)

occurCheck

private static boolean occurCheck(UnifiableVariable v,
                                  Unifiable x)

isVariableString

public static boolean isVariableString(String obj)