wugle.expression.logic
Class PropositionalLogicTreeWalker

java.lang.Object
  |
  +--antlr.TreeParser
        |
        +--wugle.expression.logic.PropositionalLogicTreeWalker

All Implemented Interfaces:

PropositionalLogicLexerTokenTypes

public class PropositionalLogicTreeWalker

extends antlr.TreeParser

implements PropositionalLogicLexerTokenTypes

Evaluates a propositional logic tree. A PropositionalLogicTreeWalker evaluates a tree conforming to the given propositional logic grammar.

Version:

0.1.4

Author:

Franz Prilmeier

Field Summary

static java.lang.String[]

_tokenNames

Fields inherited from class antlr.TreeParser

_retTree, astFactory, ASTNULL, inputState, returnAST, tokenNames, traceDepth

Fields inherited from interface wugle.expression.logic.PropositionalLogicLexerTokenTypes

AND, EOF, FALSE, IFF, IMPLIES, LITERAL, LITERAL_LETTER, LPAREN, NOT, NULL_TREE_LOOKAHEAD, OR, RPAREN, TRUE, WHITESPACE, XOR

Constructor Summary

PropositionalLogicTreeWalker()

Method Summary

Expression	expression(antlr.collections.AST _t) Evaluates expression rules.
static void	main(java.lang.String[] args) Reads a sentence in propositional logic from a file.

Methods inherited from class antlr.TreeParser

getAST, getASTFactory, getTokenName, getTokenNames, match, match, matchNot, panic, reportError, reportError, reportWarning, setASTFactory, setASTNodeClass, setASTNodeType, traceIn, traceIndent, traceOut

Methods inherited from class java.lang.Object

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

Field Detail

_tokenNames

public static final java.lang.String[] _tokenNames

Constructor Detail

PropositionalLogicTreeWalker

public PropositionalLogicTreeWalker()

Method Detail

main

public static void main(java.lang.String[] args)
                 throws antlr.RecognitionException,
                        java.io.FileNotFoundException,
                        antlr.TokenStreamException

Reads a sentence in propositional logic from a file. This method is for nothing else than demonstrating purposes. To be specific it shows how to

Parameters:

args - the command parameters. There is only one at the moment, args[ 0 ] which defines the input file name.

Throws:

antlr.RecognitionException - occurs when an input sentence is not parseable, i.e. not conforming to the given grammar.

java.io.FileNotFoundException - if the file name of the input file refers to an unknown resource.

antlr.TokenStreamException - if the input file cannot be tokenized according to the given grammar. This could be an illegal or unexpected character, for example.

expression

public final Expression expression(antlr.collections.AST _t)
                            throws antlr.RecognitionException

Evaluates expression rules. Evaluates the expression rule which is considered as the starting symbol of the grammar. To be specific this method converts the token stream / parse tree into the internal Expression data structure of WUGLE.

Returns:

the read expression. Returns a null pointer if the parse tree is empty.

antlr.RecognitionException