edu.nyu.jet.parser

Class Grammar

java.lang.Object

edu.nyu.jet.parser.Grammar

public class Grammar
extends Object

a context-free grammar.

Constructor Summary

Constructors

Constructor and Description
Grammar(Reader reader) constructs a Grammar from the data on reader.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	defines(String s) returns true if symbol s is defined (a non-terminal) in the grammar
Vector	getProductions(String LHS) returns the definition of symbol LHS in the grammar, or null if LHS is not defined in the grammar.
Vector	getProductionsEndingIn(Object element) returns a Vector of all productions whose last element is element.

Methods inherited from class java.lang.Object

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

Constructor Detail

Grammar

public Grammar(Reader reader)
        throws IOException

constructs a Grammar from the data on reader. The grammar consists of a sequence of definitions, each terminated by a semicolon. Each definition has the form
symbol := element element ... | element element ... | ... ;
where element is either a symbol or a string enclosed in double quotes ("). Note that each option (elements separated by "|") produces a separate production.

Throws:

IOException

Method Detail

getProductions

public Vector getProductions(String LHS)

returns the definition of symbol LHS in the grammar, or null if LHS is not defined in the grammar. The definition is returned as a vector of Productions.

getProductionsEndingIn

public Vector getProductionsEndingIn(Object element)

returns a Vector of all productions whose last element is element.

defines

public boolean defines(String s)

returns true if symbol s is defined (a non-terminal) in the grammar