xtc.parser
Class GrammarVisitor

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

Direct Known Subclasses:

ChoiceExpander, DeadProductionEliminator, DuplicateProductionFolder, GenericVoider, Inliner, PrefixFolder, ProductionVoider, ProductionVoider.Tester, ReferenceCounter, Renamer, RootFinder, Simplifier, TerminalOptimizer, Tokenizer, Transformer.Lifter, TransientMarker

public abstract class GrammarVisitor
extends Visitor

The parent class of all grammar module visitors. This class provides a skeleton visitor for processing grammars and self-contained modules, while maintaining a set of useful flags.

Version:

$Revision: 1.24 $

Author:

Robert Grimm

Field Summary

protected Analyzer	analyzer The analyzer utility.
protected boolean	isBound Flag for whether the current element is bound.
protected boolean	isLastElement Flag for whether the current element is the last element of a sequence.
protected boolean	isPredicate Flag for whether the current element is in a predicate.
protected boolean	isRepeatedOnce Flag for whether the current element is repeated at least once.
protected boolean	isTopLevel Flag for whether the current element is the top-level element of a production.
protected boolean	isVoided Flag for whether the current element is voided.
protected boolean	needsSequence Flag for whether the parent element requires that the directly embedded elements are sequences for code generation.
protected Runtime	runtime The runtime.
protected boolean	transformInPlace Flag for whether to transform ordered choices, repetition, and options in place, instead of creating a new production.

Constructor Summary

GrammarVisitor(Runtime runtime, Analyzer analyzer)
Create a new grammar visitor.

Method Summary

Element	visit(Binding b) Visit the specified binding.
CharCase	visit(CharCase c) Visit the specified character case.
Element	visit(CharSwitch s) Visit the specified character switch.
Element	visit(Element e) Visit the specified element.
java.lang.Object	visit(Grammar g) Visit the specified grammar.
java.lang.Object	visit(Module m) Visit the specified self-contained module.
Element	visit(Option o) Visit the specified option.
Element	visit(OrderedChoice c) Visit the specified ordered choice.
Element	visit(ParserAction pa) Visit the specified parser action.
Element	visit(Predicate p) Visit the specified predicate.
Production	visit(Production p) Visit the specified production.
Element	visit(Repetition r) Visit the specified repetition.
Element	visit(SemanticPredicate p) Visit the specified semantic predicate.
Element	visit(Sequence s) Visit the specified sequence.
Element	visit(StringMatch m) Visit the specified string match.
Element	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.

isTopLevel

protected boolean isTopLevel

Flag for whether the current element is the top-level element of a production.

isVoided

protected boolean isVoided

Flag for whether the current element is voided.

isBound

protected boolean isBound

Flag for whether the current element is bound.

isLastElement

protected boolean isLastElement

Flag for whether the current element is the last element of a sequence.

isPredicate

protected boolean isPredicate

Flag for whether the current element is in a predicate.

isRepeatedOnce

protected boolean isRepeatedOnce

Flag for whether the current element is repeated at least once.

needsSequence

protected boolean needsSequence

Flag for whether the parent element requires that the directly embedded elements are sequences for code generation. It is used by the Simplifier to avoid stripping sequences that need to be restored later on again.

transformInPlace

protected boolean transformInPlace

Flag for whether to transform ordered choices, repetition, and options in place, instead of creating a new production. This flag is used by the lifter visitor.

Constructor Detail

GrammarVisitor

public GrammarVisitor(Runtime runtime,
                      Analyzer analyzer)

Create a new grammar visitor.

Parameters:

runtime - The runtime.

analyzer - The analyzer utility.

Method Detail

visit

public java.lang.Object visit(Grammar g)

Visit the specified grammar.

visit

public java.lang.Object visit(Module m)

Visit the specified self-contained module.

visit

public Production visit(Production p)

Visit the specified production.

visit

public Element visit(OrderedChoice c)

Visit the specified ordered choice.

visit

public Element visit(Repetition r)

Visit the specified repetition.

visit

public Element visit(Option o)

Visit the specified option.

visit

public Element visit(Sequence s)

Visit the specified sequence.

visit

public Element visit(Predicate p)

Visit the specified predicate.

visit

public Element visit(SemanticPredicate p)

Visit the specified semantic predicate.

visit

public Element visit(VoidedElement v)

Visit the specified voided element.

visit

public Element visit(Binding b)

Visit the specified binding.

visit

public Element visit(StringMatch m)

Visit the specified string match.

visit

public CharCase visit(CharCase c)

Visit the specified character case.

visit

public Element visit(CharSwitch s)

Visit the specified character switch.

visit

public Element visit(ParserAction pa)

Visit the specified parser action.

visit

public Element visit(Element e)

Visit the specified element. This method provides the default implementation for nonterminals, terminals (besides character switches), node markers, actions, parse tree nodes, null literals, and value elements.