sjm.parse
Class Empty

java.lang.Object
  |
  +--sjm.parse.Parser
        |
        +--sjm.parse.Empty

public class Empty

extends Parser

An Empty parser matches any assembly once, and applies its assembler that one time.

Language elements often contain empty parts. For example, a language may at some point allow a list of parameters in parentheses, and may allow an empty list. An empty parser makes it easy to match, within the parenthesis, either a list of parameters or "empty".

Version:

1.0

Author:

Steven J. Metsker

Fields inherited from class sjm.parse.Parser

assembler, name

Constructor Summary

Empty()

Method Summary

void	accept(ParserVisitor pv, java.util.Vector visited) Accept a "visitor" and a collection of previously visited parsers.
java.util.Vector	match(java.util.Vector in) Given a set of assemblies, this method returns the set as a successful match.
protected java.util.Vector	randomExpansion(int maxDepth, int depth)
protected java.lang.String	unvisitedString(java.util.Vector visited)

Methods inherited from class sjm.parse.Parser

accept, add, best, bestMatch, completeMatch, elementClone, getName, matchAndAssemble, randomInput, setAssembler, toString, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

Empty

public Empty()

Method Detail

accept

public void accept(ParserVisitor pv,
                   java.util.Vector visited)

Accept a "visitor" and a collection of previously visited parsers.

Overrides:

accept in class Parser

Parameters:

ParserVisitor - the visitor to accept

Vector - a collection of previously visited parsers

match

public java.util.Vector match(java.util.Vector in)

Given a set of assemblies, this method returns the set as a successful match.

Overrides:

match in class Parser

Parameters:

Vector - a vector of assemblies to match against

Returns:

the input set of states

randomExpansion

protected java.util.Vector randomExpansion(int maxDepth,
                                           int depth)

Overrides:

randomExpansion in class Parser

unvisitedString

protected java.lang.String unvisitedString(java.util.Vector visited)

Overrides:

unvisitedString in class Parser