org.parboiled.matchers

Class CustomMatcher

java.lang.Object

org.parboiled.trees.ImmutableGraphNode<Matcher>

org.parboiled.matchers.AbstractMatcher

org.parboiled.matchers.CustomMatcher

All Implemented Interfaces:

Cloneable, Matcher, Rule, GraphNode<Matcher>

public abstract class CustomMatcher
extends AbstractMatcher

Base class of custom matcher implementations. If you want to implement custom matchers they have to be derived from this class. Instances of derived classes can be directly used in rule defining expressions. Caution: For performance reasons the parsing engine delegates the task of taking and restoring value stack snapshots to the matchers. If your custom matcher can run parser actions underneath it your custom matcher implementation therefore has to take care of value stack managment itselves! (See the implementation of the SequenceMatcher for hints on how to do this!)

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	CustomMatcher(Rule[] subRules, String label)
protected	CustomMatcher(Rule subRule, String label)
protected	CustomMatcher(String label)

Method Summary

Modifier and Type	Method and Description
<R> R	accept(MatcherVisitor<R> visitor) Accepts the given matcher visitor.
abstract boolean	canMatchEmpty() Determines whether this matcher instance allows empty matches.
abstract char	getStarterChar() Returns one of possibly several chars that a match can start with.
abstract boolean	isSingleCharMatcher() Determines whether this matcher instance always matches exactly one character.
abstract boolean	isStarterChar(char c) Determines whether this matcher instance can start a match with the given char.

Methods inherited from class org.parboiled.matchers.AbstractMatcher

areMismatchesMemoed, areSubnodesSuppressed, getLabel, getSubContext, getTag, hasCustomLabel, isNodeSkipped, isNodeSuppressed, label, memoMismatches, setTag, skipNode, suppressNode, suppressSubnodes, toString

Methods inherited from class org.parboiled.trees.ImmutableGraphNode

getChildren

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.parboiled.matchers.Matcher

match

Methods inherited from interface org.parboiled.trees.GraphNode

getChildren

Constructor Detail

CustomMatcher

protected CustomMatcher(String label)

CustomMatcher

protected CustomMatcher(Rule subRule,
                        String label)

CustomMatcher

protected CustomMatcher(Rule[] subRules,
                        String label)

Method Detail

isSingleCharMatcher

public abstract boolean isSingleCharMatcher()

Determines whether this matcher instance always matches exactly one character.

Returns:

true if this matcher always matches exactly one character

canMatchEmpty

public abstract boolean canMatchEmpty()

Determines whether this matcher instance allows empty matches.

Returns:

true if this matcher instance allows empty matches

isStarterChar

public abstract boolean isStarterChar(char c)

Determines whether this matcher instance can start a match with the given char.

Parameters:

c - the char

Returns:

true if this matcher instance can start a match with the given char.

getStarterChar

public abstract char getStarterChar()

Returns one of possibly several chars that a match can start with.

Returns:

a starter char

accept

public <R> R accept(MatcherVisitor<R> visitor)

Description copied from interface: Matcher

Accepts the given matcher visitor.

Parameters:

visitor - the visitor

Returns:

the value returned by the given visitor