weka.core.mathematicalexpression

Class Scanner

java.lang.Object

weka.core.mathematicalexpression.Scanner

All Implemented Interfaces:

java_cup.runtime.Scanner

public class Scanner
extends java.lang.Object
implements java_cup.runtime.Scanner

A scanner for mathematical expressions.

Version:

$Revision: 4942 $

Author:

FracPete (fracpete at waikato dot ac dot nz)

Field Summary

Fields

Modifier and Type	Field and Description
static int	YYEOF This character denotes the end of file
static int	YYINITIAL lexical states

Constructor Summary

Constructors

Constructor and Description
Scanner(java.io.InputStream in) Creates a new scanner.
Scanner(java.io.InputStream r, java_cup.runtime.SymbolFactory sf)
Scanner(java.io.Reader in) Creates a new scanner There is also a java.io.InputStream version of this constructor.

Method Summary

Modifier and Type	Method and Description
java_cup.runtime.Symbol	next_token() Resumes scanning until the next regular expression is matched, the end of input is encountered or an I/O-Error occurs.
void	yybegin(int newState) Enters a new lexical state
char	yycharat(int pos) Returns the character at position pos from the matched text.
void	yyclose() Closes the input stream.
int	yylength() Returns the length of the matched text region.
void	yypushback(int number) Pushes the specified amount of characters back into the input stream.
void	yyreset(java.io.Reader reader) Resets the scanner to read from a new input stream.
int	yystate() Returns the current lexical state.
java.lang.String	yytext() Returns the text matched by the current regular expression.

Methods inherited from class java.lang.Object

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

Field Detail

YYEOF

public static final int YYEOF

This character denotes the end of file

See Also:

Constant Field Values

YYINITIAL

public static final int YYINITIAL

lexical states

See Also:

Constant Field Values

Constructor Detail

Scanner

public Scanner(java.io.InputStream r,
               java_cup.runtime.SymbolFactory sf)

Scanner

public Scanner(java.io.Reader in)

Creates a new scanner There is also a java.io.InputStream version of this constructor.

Parameters:

in - the java.io.Reader to read input from.

Scanner

public Scanner(java.io.InputStream in)

Creates a new scanner. There is also java.io.Reader version of this constructor.

Parameters:

in - the java.io.Inputstream to read input from.

Method Detail

yyclose

public final void yyclose()
                   throws java.io.IOException

Closes the input stream.

Throws:

java.io.IOException

yyreset

public final void yyreset(java.io.Reader reader)

Resets the scanner to read from a new input stream. Does not close the old reader. All internal variables are reset, the old input stream cannot be reused (internal buffer is discarded and lost). Lexical state is set to ZZ_INITIAL.

Parameters:

reader - the new input stream

yystate

public final int yystate()

Returns the current lexical state.

yybegin

public final void yybegin(int newState)

Enters a new lexical state

Parameters:

newState - the new lexical state

yytext

public final java.lang.String yytext()

Returns the text matched by the current regular expression.

yycharat

public final char yycharat(int pos)

Returns the character at position pos from the matched text. It is equivalent to yytext().charAt(pos), but faster

Parameters:

pos - the position of the character to fetch. A value from 0 to yylength()-1.

Returns:

the character at position pos

yylength

public final int yylength()

Returns the length of the matched text region.

yypushback

public void yypushback(int number)

Pushes the specified amount of characters back into the input stream. They will be read again by then next call of the scanning method

Parameters:

number - the number of characters to be read again. This number must not be greater than yylength()!

next_token

public java_cup.runtime.Symbol next_token()
                                   throws java.io.IOException

Resumes scanning until the next regular expression is matched, the end of input is encountered or an I/O-Error occurs.

Specified by:

next_token in interface java_cup.runtime.Scanner

Returns:

the next token

Throws:

java.io.IOException - if any I/O-Error occurs