com.articulate.sigma.semRewrite

Class Literal

java.lang.Object

com.articulate.sigma.semRewrite.Literal

public class Literal
extends Object

pred(arg1,arg2). arg1 and/or arg2 can be variables which are denoted by a leading '?' The literal can be negated. It also has flags for whether it needs to be preserved, rather than consumed, during unification, and whether it has already been successfully bound to another literal during unification.

Field Summary

Fields

Modifier and Type	Field and Description
String	arg1
String	arg2
boolean	bound
boolean	negated
String	pred
boolean	preserve

Constructor Summary

Constructors

Constructor and Description
Literal()

Method Summary

Modifier and Type	Method and Description
Literal	applyBindings(HashMap<String,String> bindings)
void	applyBindingSelf(HashMap<String,String> bindings) Apply variable substitutions to a literal
Literal	deepCopy()
boolean	equals(Object o)
boolean	isGround()
static void	main(String[] args) A test method
HashMap<String,String>	mguTermList(Literal l2) Unify all terms in term1 with the corresponding terms in term2 with a common substitution.
static Literal	parse(Lexer lex, int startLine)
void	preProcessQuestionWords(List<String> qwords) If the tokens in the literal are derived from words parsed from the Stanford dependency parser, and therefore in the form word-xx, where xx are digits, prepend a '?' to signify that it's a variable.
static void	testParse() A test method for parsing a Literal
static void	testRegexUnify() A test method for wildcard unification
static void	testUnify() A test method for unification
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

negated

public boolean negated

preserve

public boolean preserve

bound

public boolean bound

pred

public String pred

arg1

public String arg1

arg2

public String arg2

Constructor Detail

Literal

public Literal()

Method Detail

toString

public String toString()

Overrides:

toString in class Object

deepCopy

public Literal deepCopy()

equals

public boolean equals(Object o)

Overrides:

equals in class Object

isGround

public boolean isGround()

Returns:

true if the clause does not contain any variables

preProcessQuestionWords

public void preProcessQuestionWords(List<String> qwords)

If the tokens in the literal are derived from words parsed from the Stanford dependency parser, and therefore in the form word-xx, where xx are digits, prepend a '?' to signify that it's a variable.

applyBindingSelf

public void applyBindingSelf(HashMap<String,String> bindings)

Apply variable substitutions to a literal

applyBindings

public Literal applyBindings(HashMap<String,String> bindings)

Returns:

a literal after applying variable substitutions to a literal

mguTermList

public HashMap<String,String> mguTermList(Literal l2)

Unify all terms in term1 with the corresponding terms in term2 with a common substitution. Note that unlike general unification, we have a fixed argument list of 2.

Returns:

the set of substitutions with the variable as the key and the binding as the value in the HashMap.

parse

public static Literal parse(Lexer lex,
                            int startLine)

Parameters:

lex - is a Lexer which has been initialized with the textual version of the Literal

startLine - is the line in the text file at which the literal appears. If it is in a large rule the start line could be different than the actual line of text for the literal. If the literal is just from a string rather than directly from a text file then the startLine will be 0.

Returns:

a Literal corresponding to the input text passed to the Lexer. Note that the predicate in this literal must already have been read

testUnify

public static void testUnify()

A test method for unification

testRegexUnify

public static void testRegexUnify()

A test method for wildcard unification

testParse

public static void testParse()

A test method for parsing a Literal

main

public static void main(String[] args)

A test method