org.nineml.coffeegrinder.parser

Class Symbol

java.lang.Object

org.nineml.coffeegrinder.util.Decoratable

org.nineml.coffeegrinder.parser.Symbol

Direct Known Subclasses:

NonterminalSymbol, TerminalSymbol

public abstract class Symbol
extends Decoratable

A grammar symbol.

Symbols match either tokens in the input (for TerminalSymbol symbols) or other symbols (for NonterminalSymbol symbols). For convenience, this interface defines both match methods for all Symbols.

Constructor Summary

Constructors

Constructor and Description
Symbol() Create a symbol with no attributes.
Symbol(java.util.Collection<ParserAttribute> attributes) Create a symbol with an initial set of attributes.

Method Summary

Modifier and Type	Method and Description
abstract boolean	matches(Symbol input) Does this symbol match the specified symbol?
abstract boolean	matches(Token input) Does this symbol match the specified token?

Methods inherited from class org.nineml.coffeegrinder.util.Decoratable

addAttribute, addAttributes, getAttribute, getAttributes, getAttributesMap, getAttributeValue, hasAttribute

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Symbol

public Symbol()

Create a symbol with no attributes.

Symbol

public Symbol(java.util.Collection<ParserAttribute> attributes)

Create a symbol with an initial set of attributes.

Parameters:

attributes - the attributes

Throws:

GrammarException - if the attribute names are not unique

AttributeException - if an attribute has an invalid value

Method Detail

matches

public abstract boolean matches(Token input)

Does this symbol match the specified token?

This is very like equality, but consider that for some kinds of symbols (for example, tokens that match regular expressions) it isn't really the same as equality.

Parameters:

input - The token.

Returns:

true if the token matches.

matches

public abstract boolean matches(Symbol input)

Does this symbol match the specified symbol?

Parameters:

input - The symbol.

Returns:

true if it is the same symbol as this symbol.