xtc.parser
Class LeftRecurser

java.lang.Object
  xtc.tree.Visitor
      xtc.parser.LeftRecurser

public class LeftRecurser
extends Visitor

Visitor to detect left-recursion in a grammar.

This visitor requires that text-only productions have been marked as such.

Version:

$Revision: 1.49 $

Author:

Robert Grimm

Field Summary

protected Analyzer	analyzer The analyzer utility.
protected Runtime	runtime The runtime.
protected boolean	terminated The flag for whether we have seen a terminal.

Constructor Summary

LeftRecurser(Runtime runtime, Analyzer analyzer)
Create a new left-recurser.

Method Summary

java.util.Set<NonTerminal>	recursive() Get the set of nonterminals corresponding to left-recursive productions.
void	visit(Binding b) Visit the specified binding.
void	visit(Element e) Visit the specified element.
void	visit(FullProduction p) Visit the specified production.
void	visit(Grammar g) Visit the specified grammar.
void	visit(Module m) Visit the specified self-contained module.
void	visit(NonTerminal nt) Visit the specified nonterminal.
void	visit(OrderedChoice c) Visit the specified ordered choice.
void	visit(ParserAction pa) Visit the specified parser action.
void	visit(Repetition r) Visit the specified repetition.
void	visit(Sequence s) Visit the specified sequence.
void	visit(StringMatch m) Visit the specified string match.
void	visit(Terminal t) Visit the specified terminal.
void	visit(UnaryOperator op) Visit the specified unary operator.
void	visit(VoidedElement v) Visit the specified voided element.

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

runtime

protected final Runtime runtime

The runtime.

analyzer

protected final Analyzer analyzer

The analyzer utility.

terminated

protected boolean terminated

The flag for whether we have seen a terminal.

Constructor Detail

LeftRecurser

public LeftRecurser(Runtime runtime,
                    Analyzer analyzer)

Create a new left-recurser.

Parameters:

runtime - The runtime.

analyzer - The analyzer utility.

Method Detail

recursive

public java.util.Set<NonTerminal> recursive()

Get the set of nonterminals corresponding to left-recursive productions. Note that this method must only be called after visiting the corresponding grammar with this visitor.

Returns:

The set of left-recursive nonterminals.

visit

public void visit(Grammar g)

Visit the specified grammar.

visit

public void visit(Module m)

Visit the specified self-contained module.

visit

public void visit(FullProduction p)

Visit the specified production.

visit

public void visit(OrderedChoice c)

Visit the specified ordered choice.

visit

public void visit(Repetition r)

Visit the specified repetition.

visit

public void visit(Sequence s)

Visit the specified sequence.

visit

public void visit(VoidedElement v)

Visit the specified voided element.

visit

public void visit(Binding b)

Visit the specified binding.

visit

public void visit(StringMatch m)

Visit the specified string match.

visit

public void visit(NonTerminal nt)

Visit the specified nonterminal.

visit

public void visit(Terminal t)

Visit the specified terminal.

visit

public void visit(UnaryOperator op)

Visit the specified unary operator. This method provides the default implementation for options and predicates.

visit

public void visit(ParserAction pa)

Visit the specified parser action. Parser actions are assumed to always consume some input.

visit

public void visit(Element e)

Visit the specified element. This method provides the default implementation for node markers, actions, parse tree nodes, null literals, and value elements.