grammarscope.io.read

Class TreeReader

java.lang.Object

grammarscope.io.read.TreeReader

public class TreeReader
extends java.lang.Object

This class implements the TreeReader interface to read Penn Treebank-style files. The reader is implemented as a pushdown automaton (PDA) that parses the Lisp-style format in which the trees are stored. This reader is compatible with both PTB and PATB trees.

Author:

Christopher Manning, Roger Levy, Spence Green, Bernard Bou for adaptation

Field Summary

Fields

Modifier and Type	Field and Description
private MutableAParseTree	currentTree
private static java.lang.String	leftParen
private static java.lang.String	rightParen
private java.util.ArrayList<MutableAParseTree>	stack
private Tokenizer<java.lang.String>	tokenizer
private TreeNormalizer	treeNormalizer

Constructor Summary

Constructors

Constructor and Description
TreeReader(java.io.StringReader stringReader) Constructor

Method Summary

Modifier and Type	Method and Description
private AParseTree	getTreeFromInputStream()
static void	main(java.lang.String[] args)
static AParseTree	make(java.lang.String inputString) This gives you a tree from a String representation (as a bracketed Tree, of the kind produced by toString(), pennPrint(), or as in the Penn Treebank.
AParseTree	readTree() Reads a single tree in standard Penn Treebank format from the input stream.

Methods inherited from class java.lang.Object

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

Field Detail

tokenizer

private final Tokenizer<java.lang.String> tokenizer

treeNormalizer

private final TreeNormalizer treeNormalizer

currentTree

private MutableAParseTree currentTree

stack

private java.util.ArrayList<MutableAParseTree> stack

leftParen

private static final java.lang.String leftParen

See Also:

Constant Field Values

rightParen

private static final java.lang.String rightParen

See Also:

Constant Field Values

Constructor Detail

TreeReader

public TreeReader(java.io.StringReader stringReader)

Constructor

Parameters:

stringReader - string reader

Method Detail

make

public static AParseTree make(java.lang.String inputString)

This gives you a tree from a String representation (as a bracketed Tree, of the kind produced by toString(), pennPrint(), or as in the Penn Treebank. It's not the most efficient thing to do for heavy duty usage.

Parameters:

inputString - input string

Returns:

parse tree artifact

readTree

public AParseTree readTree()
                    throws java.io.IOException

Reads a single tree in standard Penn Treebank format from the input stream. The method supports additional parentheses around the tree (an unnamed ROOT node) so long as they are balanced. If the token stream ends before the current tree is complete, then the method will throw an IOException.

Note that the method will skip malformed trees and attempt to read additional trees from the input stream. It is possible, however, that a malformed tree will corrupt the token stream. In this case, an IOException will eventually be thrown.

Returns:

A single tree, or null at end of token stream.

Throws:

java.io.IOException - exception

getTreeFromInputStream

private AParseTree getTreeFromInputStream()

main

public static void main(java.lang.String[] args)