org.nineml.coffeegrinder.parser

Class EarleyParser

java.lang.Object

org.nineml.coffeegrinder.parser.EarleyParser

All Implemented Interfaces:

GearleyParser

public class EarleyParser
extends java.lang.Object
implements GearleyParser

The Earley parser.

The Earley parser compares an input sequence against a grammar and determines if the input is a sentence in the grammar.

This is a fairly literal implementation of the parser in §5 of SPPF-Style Parsing From Earley Recognisers.

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	logcategory

Method Summary

Modifier and Type	Method and Description
int	getColumnNumber() Returns the column number of the last character on the last line read by the parser.
ParserGrammar	getGrammar() Get the grammar used by this parser.
int	getLineNumber() Returns the line number of the last line read by the parser.
int	getOffset() Returns the last offset read by the parser.
ParserType	getParserType() Return the parser type.
NonterminalSymbol	getSeed() Get the NonterminalSymbol seed value used by this parser.
boolean	hasMoreInput() Is there more input?
EarleyResult	parse(java.util.Iterator<Token> input) Parse a sequence of tokens against the grammar.
EarleyResult	parse(java.lang.String input) Parse an input string against the grammar.
EarleyResult	parse(Token[] input) Parse an array of tokens against the grammar.

Methods inherited from class java.lang.Object

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

Field Detail

logcategory

public static final java.lang.String logcategory

See Also:

Constant Field Values

Method Detail

getParserType

public ParserType getParserType()

Return the parser type.

Specified by:

getParserType in interface GearleyParser

Returns:

ParserType.Earley

getGrammar

public ParserGrammar getGrammar()

Get the grammar used by this parser.

Specified by:

getGrammar in interface GearleyParser

Returns:

the grammar

getSeed

public NonterminalSymbol getSeed()

Get the NonterminalSymbol seed value used by this parser.

Specified by:

getSeed in interface GearleyParser

Returns:

the seed

parse

public EarleyResult parse(java.lang.String input)

Parse an input string against the grammar.

This is a shortcut for parsing a sequence of characters.

Specified by:

parse in interface GearleyParser

Parameters:

input - the input string

Returns:

a parse result

parse

public EarleyResult parse(Token[] input)

Parse an array of tokens against the grammar.

You must not change the input array.

Specified by:

parse in interface GearleyParser

Parameters:

input - the input array

Returns:

a parse result

parse

public EarleyResult parse(java.util.Iterator<Token> input)

Parse a sequence of tokens against the grammar.

Specified by:

parse in interface GearleyParser

Parameters:

input - the input sequence

Returns:

a parse result

hasMoreInput

public boolean hasMoreInput()

Is there more input?

If the parse succeeded, the answer will always be false. But a failed parse can fail because it was unable to process a token or because it ran out of tokens. This method checks if there was any more input after the parse completed.

Specified by:

hasMoreInput in interface GearleyParser

Returns:

true if parsing failed before the entire input was consumed

getLineNumber

public int getLineNumber()

Description copied from interface: GearleyParser

Returns the line number of the last line read by the parser.

Specified by:

getLineNumber in interface GearleyParser

Returns:

the line number.

getColumnNumber

public int getColumnNumber()

Description copied from interface: GearleyParser

Returns the column number of the last character on the last line read by the parser.

Specified by:

getColumnNumber in interface GearleyParser

Returns:

the column number.

getOffset

public int getOffset()

Description copied from interface: GearleyParser

Returns the last offset read by the parser.

Specified by:

getOffset in interface GearleyParser

Returns:

the offset.