jeops.compiler.parser
Class Scanner

java.lang.Object
  |
  +--jeops.compiler.parser.Scanner

public class Scanner

extends java.lang.Object

implements TokenConstants

Class used in the parsing of the rules file. It's the first step in the converting of the rules into Java classes.

Version:

0.01 04.01.2000

Author:

Carlos Figueira Filho (csff@cin.ufpe.br)

Field Summary

private java.lang.StringBuffer	buffer The string buffer used in the scanning of the file.
private int	currentColumn The current column from the file.
private int	currentLine The current line from the file.
private Token	currentToken The current token.
private char	lastChar The last char read from the file.
private Token	lastNonWhiteSpaceToken The last non-whitespace token.
private java.io.BufferedReader	reader The reader used to get the characters from the rules file.
private static java.lang.String[]	reservedWords The list of reserved words.
private java.lang.String	ruleFileName The name of the rules file.
private int	tokenColumn The column of the first character in the current token.
private int	tokenLine The line of the first character in the current token.
private static int[]	typeReservedWords The token types of the reserved words.

Fields inherited from interface jeops.compiler.parser.TokenConstants

ACTIONS, ASTERISK, CLOSE_CURLY_BRACKET, COMMA, COMMENT, CONDITIONS, DECLARATIONS, DOT, EOF, EQUALS, ERROR, EXTENDS, IDENT, IMPLEMENTS, IMPORT, LOCALDECL, NONE_ABOVE, OPEN_CURLY_BRACKET, PACKAGE, PUBLIC, RULE, RULE_BASE, SEMICOLON, STRING, WHITE_SPACE

Constructor Summary

Scanner(java.lang.String ruleFileName)
Class constructor.

Method Summary

private int	checkReserved(java.lang.String id) Checks whether a given identifier is a reserved word.
int	getCurrentColumn() Returns the current column from the file.
int	getCurrentLine() Returns the current line from the file.
Token	getLastNonWhiteSpaceToken() Returns the last non-whitespace token.
private Token	idOrReserved(java.lang.String str) Returns a token that can be an identifier or a reserved word.
static void	main(java.lang.String[] args) Test method for this class.
Token	nextToken() Returns the next token from the file.
private void	readNextChar() Reads the next char in the file, storing it in "lastChar".

Methods inherited from class java.lang.Object

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

Field Detail

currentToken

private Token currentToken

The current token.

ruleFileName

private java.lang.String ruleFileName

The name of the rules file.

reader

private java.io.BufferedReader reader

The reader used to get the characters from the rules file.

buffer

private java.lang.StringBuffer buffer

The string buffer used in the scanning of the file.

lastChar

private char lastChar

The last char read from the file.

tokenLine

private int tokenLine

The line of the first character in the current token.

currentLine

private int currentLine

The current line from the file.

tokenColumn

private int tokenColumn

The column of the first character in the current token.

currentColumn

private int currentColumn

The current column from the file.

lastNonWhiteSpaceToken

private Token lastNonWhiteSpaceToken

The last non-whitespace token. A whitespace token is one of type COMMENT or WHITE_SPACE.

reservedWords

private static final java.lang.String[] reservedWords

The list of reserved words.

typeReservedWords

private static final int[] typeReservedWords

The token types of the reserved words.

Constructor Detail

Scanner

public Scanner(java.lang.String ruleFileName)
        throws java.io.IOException

Class constructor.

Parameters:

ruleFileName - the name of the rules file.

Throws:

java.io.IOException - if some IO error occurs.

Method Detail

checkReserved

private int checkReserved(java.lang.String id)

Checks whether a given identifier is a reserved word.

Parameters:

id - the identifier to be checked.

Returns:

the token type relative to the given word, if it's a reserved word, or -1 if it's not a reserved word.

getCurrentColumn

public int getCurrentColumn()

Returns the current column from the file.

Returns:

the current column from the file.

getCurrentLine

public int getCurrentLine()

Returns the current line from the file.

Returns:

the current line from the file.

getLastNonWhiteSpaceToken

public Token getLastNonWhiteSpaceToken()

Returns the last non-whitespace token. A whitespace token is one whose type is COMMENT or WHITE_SPACE.

Returns:

the last non-whitespace token.

idOrReserved

private Token idOrReserved(java.lang.String str)

Returns a token that can be an identifier or a reserved word.

Parameters:

str - the string that represents either an identifier or a reserved word.

Returns:

a token that can be an identifier or a reserved word.

main

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

Test method for this class.

Parameters:

args - command-line arguments. None is needed, but one can pass the rule file name for the scanning.

nextToken

public Token nextToken()
                throws java.io.IOException

Returns the next token from the file.

Returns:

the next token from the file.

Throws:

java.io.IOException - if some IO error occurs.

readNextChar

private void readNextChar()
                   throws java.io.IOException

Reads the next char in the file, storing it in "lastChar".

Throws:

java.io.IOException - if some IO error occurs.