org.extex.ocpware.compiler.parser
Class ParserStream

java.lang.Object
  java.io.InputStream
      java.io.FilterInputStream
          java.io.PushbackInputStream
              org.extex.ocpware.compiler.parser.ParserStream

All Implemented Interfaces:

java.io.Closeable

public class ParserStream
extends java.io.PushbackInputStream

This class provides a push-back input stream which can parse certain basic entities.

Version:

$Revision:6007 $

Author:

Gerd Neugebauer

Field Summary

Fields inherited from class java.io.PushbackInputStream

buf, pos

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

ParserStream(java.io.InputStream in)
Creates a new object.

Method Summary

SyntaxException	error(int c) Create an exception containing the context.
void	expect(char ex) Skip to the next non-white-space character and compare it to a given one.
void	expect(java.lang.String ex) Parse an id.
java.lang.CharSequence	getLine() Getter for line.
int	getLineno() Getter for lineno.
java.lang.String	parseId() Parse an id.
int	parseNumber(int cc) Parse a number.
java.lang.String	parseString() Parse a string specification.
int	read()
int	skipSpace() Skip whitespace and comments and advance to the next real character.
java.lang.String	toString()
void	unread(int b)

Methods inherited from class java.io.PushbackInputStream

available, close, mark, markSupported, read, reset, skip, unread, unread

Methods inherited from class java.io.FilterInputStream

read

Methods inherited from class java.lang.Object

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

Constructor Detail

ParserStream

public ParserStream(java.io.InputStream in)

Creates a new object.

Parameters:

in - the stream to acquire characters from

Method Detail

error

public SyntaxException error(int c)

Create an exception containing the context.

Parameters:

c - the character read

Returns:

the exception

expect

public void expect(char ex)
            throws java.io.IOException,
                   SyntaxException

Skip to the next non-white-space character and compare it to a given one. If the comparison fails then an exception is raised.

Parameters:

ex - the expected character

Throws:

java.io.IOException - in case of an I/O error

SyntaxException - in case of a syntax error

expect

public void expect(java.lang.String ex)
            throws java.io.IOException,
                   SyntaxException

Parse an id.

Parameters:

ex - the expected characters

Throws:

java.io.IOException - in case of an I/O error

SyntaxException - in case of a syntax error

getLine

public java.lang.CharSequence getLine()

Getter for line.

Returns:

the line

getLineno

public int getLineno()

Getter for lineno.

Returns:

the lineno

parseId

public java.lang.String parseId()
                         throws java.io.IOException,
                                SyntaxException

Parse an id. An id is a non empty sequence of characters made up of letters (a-z,A-Z), digits (0-9), the underscore character(_), and the colon (:) where the first character is not a digit or a colon.

Returns:

the identifier read

Throws:

java.io.IOException - in case of an I/O error

SyntaxException - in case of a syntax error

parseNumber

public int parseNumber(int cc)
                throws java.io.IOException,
                       SyntaxException

Parse a number.

Parameters:

cc - the character already scanned

Returns:

the number read

Throws:

java.io.IOException - in case of an I/O error

SyntaxException - in case of an parser error

parseString

public java.lang.String parseString()
                             throws java.io.IOException

Parse a string specification. It is assumed that the starting double quote (") has already been digested. The string reaches to the terminating double quote. This terminating character is absorbed but not included into the result.

If two double quotes occur in sequence then this is interpreted as one double quote character embedded in the string.

Returns:

the string value

Throws:

java.io.IOException - in case of an I/O error

read

public int read()
         throws java.io.IOException

Overrides:

read in class java.io.PushbackInputStream

Throws:

java.io.IOException

See Also:

PushbackInputStream.read()

skipSpace

public int skipSpace()
              throws java.io.IOException

Skip whitespace and comments and advance to the next real character. This character is returned. If end of file is reached -1 is returned.

Returns:

the character read or -1 upon EOF

Throws:

java.io.IOException - in case of an I/O error

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

See Also:

Object.toString()

unread

public void unread(int b)
            throws java.io.IOException

Overrides:

unread in class java.io.PushbackInputStream

Throws:

java.io.IOException

See Also:

PushbackInputStream.unread(int)