/*****************************************************************************
* *
* This file is part of the BeanShell Java Scripting distribution. *
* Documentation and updates may be found at http://www.beanshell.org/ *
* *
* Sun Public License Notice: *
* *
* The contents of this file are subject to the Sun Public License Version *
* 1.0 (the "License"); you may not use this file except in compliance with *
* the License. A copy of the License is available at http://www.sun.com *
* *
* The Original Code is BeanShell. The Initial Developer of the Original *
* Code is Pat Niemeyer. Portions created by Pat Niemeyer are Copyright *
* (C) 2000. All Rights Reserved. *
* *
* GNU Public License Notice: *
* *
* Alternatively, the contents of this file may be used under the terms of *
* the GNU Lesser General Public License (the "LGPL"), in which case the *
* provisions of LGPL are applicable instead of those above. If you wish to *
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* Patrick Niemeyer (pat@pat.net) *
* Author of Learning Java, O'Reilly & Associates *
* http://www.pat.net/~pat/ *
* *
*****************************************************************************/
package org.gjt.sp.jedit.bsh;
import java.io.*;
/**
This is a quick hack to turn empty lines entered interactively on the
command line into ';\n' empty lines for the interpreter. It's just more
pleasant to be able to hit return on an empty line and see the prompt
reappear.
This is *not* used when text is sourced from a file non-interactively.
*/
class CommandLineReader extends FilterReader {
public CommandLineReader( Reader in ) {
super(in);
}
static final int
normal = 0,
lastCharNL = 1,
sentSemi = 2;
int state = lastCharNL;
public int read() throws IOException {
int b;
if ( state == sentSemi ) {
state = lastCharNL;
return '\n';
}
// skip CR
while ( (b = in.read()) == '\r' );
if ( b == '\n' )
if ( state == lastCharNL ) {
b = ';';
state = sentSemi;
} else
state = lastCharNL;
else
state = normal;
return b;
}
/**
This is a degenerate implementation.
I don't know how to keep this from blocking if we try to read more
than one char... There is no available() for Readers ??
*/
public int read(char buff[], int off, int len) throws IOException
{
int b = read();
if ( b == -1 )
return -1; // EOF, not zero read apparently
else {
buff[off]=(char)b;
return 1;
}
}
// Test it
public static void main( String [] args ) throws Exception {
Reader in = new CommandLineReader( new InputStreamReader(System.in) );
while ( true )
System.out.println( in.read() );
}
}