xtc.parser
Class ProductionVoider

java.lang.Object
  xtc.tree.Visitor
      xtc.parser.GrammarVisitor
          xtc.parser.ProductionVoider

public class ProductionVoider
extends GrammarVisitor

Visitor to turn the semantic value of a production to void. This visitor converts non-void productions whose semantic values are never bound to void productions. As a practical matter, it only converts productions that do not contain (parser) actions.

This visitor assumes that the entire grammar is contained in a single module.

Version:

$Revision: 1.39 $

Author:

Robert Grimm

Nested Class Summary

static class

ProductionVoider.Tester Visitor to determine which productions are voidable.

Field Summary

Fields inherited from class xtc.parser.GrammarVisitor

analyzer, isBound, isLastElement, isPredicate, isRepeatedOnce, isTopLevel, isVoided, needsSequence, runtime, transformInPlace

Constructor Summary

ProductionVoider(Runtime runtime, Analyzer analyzer)
Create a new production voider.

Method Summary

Element	visit(Binding b) Visit the specified binding.
java.lang.Object	visit(Module m) Visit the specified grammar.
Element	visit(ValueElement e) Visit the specified value element.
Element	visit(VoidedElement v) Visit the specified voided element.

Methods inherited from class xtc.parser.GrammarVisitor

visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit, visit

Methods inherited from class xtc.tree.Visitor

dispatch, equals, hashCode, iterate, map, mapInPlace, unableToVisit, visit

Methods inherited from class java.lang.Object

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

Constructor Detail

ProductionVoider

public ProductionVoider(Runtime runtime,
                        Analyzer analyzer)

Create a new production voider.

Parameters:

runtime - The runtime.

analyzer - The analyzer utility.

Method Detail

visit

public java.lang.Object visit(Module m)

Visit the specified grammar.

Overrides:

visit in class GrammarVisitor

visit

public Element visit(VoidedElement v)

Visit the specified voided element.

Overrides:

visit in class GrammarVisitor

visit

public Element visit(Binding b)

Visit the specified binding.

Overrides:

visit in class GrammarVisitor

visit

public Element visit(ValueElement e)

Visit the specified value element.