Symbol (CoffeeGrinder, Earley and GLL parsers in Java)

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	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

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`abstract void`	`export(GrammarExporter exporter)`	Export this symbol with the specified exporter.
`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.
  - export
```
public abstract void export(GrammarExporter exporter)
```
    Export this symbol with the specified exporter.
    
    Parameters:
    
    exporter - the exporter.