de.up.ling.irtg.codec

Class PcfgIrtgInputCodec

java.lang.Object

de.up.ling.irtg.codec.InputCodec<InterpretedTreeAutomaton>

de.up.ling.irtg.codec.PcfgIrtgInputCodec

public class PcfgIrtgInputCodec
extends InputCodec<InterpretedTreeAutomaton>

An input codec for context-free grammars, with or without rule probabilities. The first line of a file that this codec will read contains the start symbol of the grammar. Then one rule is specified on each line, in the following form:

A -> B c D [0.3]

Rule probabilities may optionally be specified in square brackets for each rule. Rules without explicit probabilities receive weight 1; this can be used to specify an ordinary, non-probabilistic context-free grammar.

The codec infers which symbols are nonterminals by taking all symbols that occur on the left-hand side of a rule as nonterminals. This means that the terminal and nonterminal symbols must be disjoint sets, otherwise the grammar will not be equivalent to what you intended.

The codec represents the context-free grammar as an IRTG with a single interpretation called "string" over a StringAlgebra. This algebra has only a single concatenation operator, "*"; it has arity 2. You may still use multiple symbols on the right-hand side of your CFG rules. These will be combined together using binary concatenations in an unspecified bracketing.

Author:

koller

Constructor Summary

Constructors

Constructor and Description
PcfgIrtgInputCodec()

Method Summary

Modifier and Type	Method and Description
static void	main(String[] args)
InterpretedTreeAutomaton	read(InputStream is) Reads an object from an input stream.

Methods inherited from class de.up.ling.irtg.codec.InputCodec

addOptions, getAllInputCodecs, getInputCodecByExtension, getInputCodecByName, getInputCodecByNameOrExtension, getInputCodecs, getMetadata, getOption, hasTrueOption, read, setOption, setProgressListener

Methods inherited from class java.lang.Object

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

Constructor Detail

PcfgIrtgInputCodec

public PcfgIrtgInputCodec()

Method Detail

read

public InterpretedTreeAutomaton read(InputStream is)
                              throws CodecParseException,
                                     IOException

Description copied from class: InputCodec

Reads an object from an input stream.

Specified by:

read in class InputCodec<InterpretedTreeAutomaton>

Returns:

Throws:

CodecParseException - if an error occurred while decoding the input stream into an object

IOException - if an error occurred while reading data from the input stream

main

public static void main(String[] args)
                 throws Exception

Throws:

Exception