simple.lexer
Class Lexer

java.lang.Object
  simple.lexer.Lexer

public class Lexer
extends java.lang.Object

This class defines a lexer object that will do a lexical analysis on a stream of characters, and generates Tokens following the rule:

Character	Token
(	Token.Type.LPAREN
)	Token.Type.RPAREN
[+-]	Token.Type.TERMOP
[*/]	Token.Type.FACTOP
[0-9]	Token.Type.NUMBER
<EOF>	Token.Type.EOF

Author:

Santoso Wijaya

See Also:

Token, Token.Type

Constructor Summary

Lexer(java.lang.String src)
Creates a lexer object, passing a source string.

Method Summary

Token	getNextToken()
boolean	hasMoreTokens()

Methods inherited from class java.lang.Object

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

Constructor Detail

Lexer

public Lexer(java.lang.String src)
      throws ParseException

Creates a lexer object, passing a source string.

Parameters:

src - the source string

Throws:

ParseException - if unrecognized character is found

Method Detail

hasMoreTokens

public boolean hasMoreTokens()

Returns:

true if there is more token(s) to be returned

getNextToken

public Token getNextToken()

Returns:

null if there is no more token.