Package easyIO

Class Scanner

java.lang.Object

easyIO.BacktrackScanner

easyIO.Scanner

public class Scanner
extends BacktrackScanner

A BacktrackScanner extended with convenience methods for parsing common things like integers and identifiers. Compared to a java.util.Scanner, it has the ability to peek() at the next character on the input and the ability to read its input from multiple Readers, which may be added on the fly. Beyond this, it can also do arbitary lookahead and rollback of the input stream using the mark(), accept(), and abort() methods from BacktrackScanner. Generally, all methods parse input starting at the current position, and throw UnexpectedInput if the expected input is not found. If an exception is thrown, the current input position is left unchanged.

Nested Class Summary

Nested classes/interfaces inherited from class easyIO.BacktrackScanner

BacktrackScanner.Location

Constructor Summary

Constructors

Constructor	Description
Scanner()
Scanner(java.io.Reader r, java.lang.String name)	Create scanner that reads from source input r, calling the source name.
Scanner(java.lang.String filename)	Create scanner that reads from file named filename.

Method Summary

Modifier and Type	Method	Description
void	consume(java.lang.String s)	Scan past the specified string.
void	digits()	Scan one or more digits.
void	eol()	Scan to the end of the current line or to the end of the input, whichever is first.
void	floatingPoint()	Scan a floating-point number.
void	identifier()	Scan an identifier ala Java.
void	integer()	Scan past an integer constant.
void	newline()	Scan past a optional carriage return character and a newline character.
char	nextDigit()	Scan past and return the next character if it is a digit.
double	nextDouble()	Scan past a floating-point constant and return its value as a double
java.lang.String	nextIdentifier()	Scan past and return an identifier.
int	nextInt()	Scan past an integer constant and return its value.
java.lang.String	nextLine()	Scan past and return all text from the current position to the next newline character.
void	optDigits()	Scan past all digits at the current posn, if any.
void	trailingWhitespace()	Scan past any whitespace up to the end of the line, the end of the file, or the next non-whitespace character.
void	whitespace()	Scan past any whitespace.

Methods inherited from class easyIO.BacktrackScanner

abort, accept, advance, appendSource, charPos, close, depth, dump, getMarkLocation, getToken, hasNext, includeSource, invariant, lineNo, location, mark, next, peek, source, string, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

Scanner

public Scanner()

Scanner

public Scanner(java.io.Reader r,
               java.lang.String name)

Create scanner that reads from source input r, calling the source name.

Scanner

public Scanner(java.lang.String filename)
        throws java.io.FileNotFoundException

Create scanner that reads from file named filename. To read directly from a string, use a StringReader.

Throws:

java.io.FileNotFoundException

See Also:

StringReader

Method Detail

whitespace

public void whitespace()

Scan past any whitespace.

consume

public void consume(java.lang.String s)
             throws UnexpectedInput

Scan past the specified string.

Throws:

UnexpectedInput - if anything other than the expected string is encountered, leaving the scanner at the position where an unexpected character is reached.

nextDigit

public char nextDigit()
               throws UnexpectedInput

Scan past and return the next character if it is a digit.

Throws:

UnexpectedInput

optDigits

public void optDigits()

Scan past all digits at the current posn, if any.

integer

public void integer()
             throws UnexpectedInput

Scan past an integer constant.

Throws:

UnexpectedInput - if the characters at the current position are not a integer literal.

floatingPoint

public void floatingPoint()
                   throws UnexpectedInput

Scan a floating-point number.

Throws:

UnexpectedInput - if the characters at the current position are not a floating-point literal.

digits

public void digits()
            throws UnexpectedInput

Scan one or more digits.

Throws:

UnexpectedInput - if the next character is not a digit.

identifier

public void identifier()
                throws UnexpectedInput

Scan an identifier ala Java.

Throws:

UnexpectedInput - if the next characters are not an identifier.

nextInt

public int nextInt()
            throws UnexpectedInput

Scan past an integer constant and return its value.

Throws:

UnexpectedInput - if the characters following the current position are not an integer literal.

nextDouble

public double nextDouble()
                  throws UnexpectedInput

Scan past a floating-point constant and return its value as a double

Throws:

UnexpectedInput - if the characters following the current position are not a legal representation of a double literal.

nextLine

public java.lang.String nextLine()
                          throws UnexpectedInput

Scan past and return all text from the current position to the next newline character.

Throws:

UnexpectedInput - if there is no terminated line after the current position.

nextIdentifier

public java.lang.String nextIdentifier()
                                throws UnexpectedInput

Scan past and return an identifier.

Throws:

UnexpectedInput - if the characters at the current position are not a legal Java identifier.

newline

public void newline()
             throws UnexpectedInput

Scan past a optional carriage return character and a newline character.

Throws:

UnexpectedInput - if the next characters are neither "\r\n" nor "\n".

eol

public void eol()

Scan to the end of the current line or to the end of the input, whichever is first.

trailingWhitespace

public void trailingWhitespace()

Scan past any whitespace up to the end of the line, the end of the file, or the next non-whitespace character.