xtc.parser
Class RootFinder

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

public class RootFinder
extends GrammarVisitor

Visitor to identify a grammar's real root. A real root is a top-level nonterminal, whose production directly or indirectly depends on all other top-level nonterminals. If a grammar has such a root, this visitor annotates the grammar with the root property.

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

Version:

$Revision: 1.12 $

Author:

Robert Grimm

Field Summary

protected java.util.Set<NonTerminal>

topLevel The set of qualified top-level nonterminals.

Fields inherited from class xtc.parser.GrammarVisitor

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

Constructor Summary

RootFinder(Runtime runtime, Analyzer analyzer)
Create a new root finder.

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

Field Detail

topLevel

protected java.util.Set<NonTerminal> topLevel

The set of qualified top-level nonterminals.

Constructor Detail

RootFinder

public RootFinder(Runtime runtime,
                  Analyzer analyzer)

Create a new root finder.

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.