xtc.parser
Class DeadProductionEliminator

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

public class DeadProductionEliminator
extends GrammarVisitor

Visitor to eliminate dead productions. This visitor eliminates productions that are not reachable from top-level productions. It may perform faster if the grammar has previously been annotated with its real root.

Version:

$Revision: 1.39 $

Author:

Robert Grimm

See Also:

RootFinder

Field Summary

Fields inherited from class xtc.parser.GrammarVisitor

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

Constructor Summary

DeadProductionEliminator(Runtime runtime, Analyzer analyzer)
Create a new dead production eliminator.

Method Summary

java.lang.Object	visit(Module m) Visit the specified grammar.
Element	visit(NonTerminal nt) Visit the specified nonterminal.

Methods inherited from class xtc.parser.GrammarVisitor

visit, visit, 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

DeadProductionEliminator

public DeadProductionEliminator(Runtime runtime,
                                Analyzer analyzer)

Create a new dead production eliminator.

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(NonTerminal nt)

Visit the specified nonterminal.