aima.core.logic.common

Class Parser<S>

java.lang.Object

aima.core.logic.common.Parser<S>

Type Parameters:

S - the root type of the abstract syntax tree being parsed.

Direct Known Subclasses:

PLParser

public abstract class Parser<S>
extends java.lang.Object

An abstract base class for constructing parsers for knowledge representation languages. It provides a mechanism for converting a sequence of tokens (derived from an appropriate lexer) into a syntactically correct abstract syntax tree of the representation language.

Author:

Ravi Mohan, Ciaran O'Reilly

Field Summary

Fields

Modifier and Type	Field and Description
protected int	lookAheadBufferSize

Constructor Summary

Constructors

Constructor and Description
Parser()

Method Summary

Modifier and Type	Method and Description
protected void	consume() Consume 1 token from the input.
abstract Lexer	getLexer()
protected Token	lookAhead(int i)
protected void	match(java.lang.String toMatchSymbol) Consume the given match symbol if it matches the current input token.
protected abstract S	parse() To be implemented by concrete implementations of this class.
S	parse(java.io.Reader inputReader) Parse the input concrete syntax into an abstract syntax tree.
S	parse(java.lang.String input) Parse the input concrete syntax into an abstract syntax tree.

Methods inherited from class java.lang.Object

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

Field Detail

lookAheadBufferSize

protected int lookAheadBufferSize

Constructor Detail

Parser

public Parser()

Method Detail

getLexer

public abstract Lexer getLexer()

Returns:

an instance of the Lexer to be used by a concrete implementation of this class.

parse

public S parse(java.lang.String input)

Parse the input concrete syntax into an abstract syntax tree.

Parameters:

input - a string representation of the concrete syntax to be parsed.

Returns:

the root node of an abstract syntax tree representation of the the concrete input syntax that was parsed.

parse

public S parse(java.io.Reader inputReader)

Parse the input concrete syntax into an abstract syntax tree.

Parameters:

inputReader - a Reader of the concrete syntax to be parsed.

Returns:

the root node of an abstract syntax tree representation of the the concrete input syntax that was parsed.

parse

protected abstract S parse()

To be implemented by concrete implementations of this class.

Returns:

the root node of an abstract syntax tree representation of the the concrete input syntax that was parsed.

lookAhead

protected Token lookAhead(int i)

Returns:

the token at the specified position in the lookahead buffer.

consume

protected void consume()

Consume 1 token from the input.

match

protected void match(java.lang.String toMatchSymbol)

Consume the given match symbol if it matches the current input token. If it does not match throws a ParserException detailing the match error.

Parameters:

toMatchSymbol - the symbol to match before consuming it.