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* The AIBench Shell Plugin
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/*****************************************************************************
* *
* 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. *
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* 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 *
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* Patrick Niemeyer ([email protected]) *
* Author of Learning Java, O'Reilly & Associates *
* http://www.pat.net/~pat/ *
* *
*****************************************************************************/
package bsh;
/**
* Implementation of the for(;;) statement.
*/
class BSHForStatement extends SimpleNode implements ParserConstants {
public boolean hasForInit;
public boolean hasExpression;
public boolean hasForUpdate;
private SimpleNode forInit;
private SimpleNode expression;
private SimpleNode forUpdate;
private SimpleNode statement;
private boolean parsed;
BSHForStatement(int id) {
super(id);
}
public Object eval(CallStack callstack, Interpreter interpreter) throws EvalError {
int i = 0;
if (hasForInit)
forInit = ((SimpleNode) jjtGetChild(i++));
if (hasExpression)
expression = ((SimpleNode) jjtGetChild(i++));
if (hasForUpdate)
forUpdate = ((SimpleNode) jjtGetChild(i++));
if (i < jjtGetNumChildren()) // should normally be
statement = ((SimpleNode) jjtGetChild(i));
NameSpace enclosingNameSpace = callstack.top();
BlockNameSpace forNameSpace = new BlockNameSpace(enclosingNameSpace);
/*
* Note: some interesting things are going on here.
*
* 1) We swap instead of push... The primary mode of operation
* acts like we are in the enclosing namespace... (super must be
* preserved, etc.)
*
* 2) We do *not* call the body block eval with the namespace
* override. Instead we allow it to create a second subordinate
* BlockNameSpace child of the forNameSpace. Variable
* propogation still works through the chain, but the block's
* child cleans the state between iteration. (which is correct
* Java behavior... see forscope4.bsh)
*/
// put forNameSpace it on the top of the stack
// Note: it's important that there is only one exit point from
// this
// method so that we can swap back the namespace.
callstack.swap(forNameSpace);
// Do the for init
if (hasForInit)
forInit.eval(callstack, interpreter);
Object returnControl = Primitive.VOID;
while (true) {
if (hasExpression) {
boolean cond = BSHIfStatement.evaluateCondition(expression, callstack, interpreter);
if (!cond)
break;
}
boolean breakout = false; // switch eats a
// multi-level break
// here?
if (statement != null) // not empty statement
{
// do *not* invoke special override for block...
// (see above)
Object ret = statement.eval(callstack, interpreter);
if (ret instanceof ReturnControl) {
switch (((ReturnControl) ret).kind) {
case RETURN:
returnControl = ret;
breakout = true;
break;
case CONTINUE:
break;
case BREAK:
breakout = true;
break;
}
}
}
if (breakout)
break;
if (hasForUpdate)
forUpdate.eval(callstack, interpreter);
}
callstack.swap(enclosingNameSpace); // put it back
return returnControl;
}
}
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