/*****************************************************************************
* *
* 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 *
* allow use of your version of this file only under the terms of the LGPL *
* and not to allow others to use your version of this file under the SPL, *
* indicate your decision by deleting the provisions above and replace *
* them with the notice and other provisions required by the LGPL. If you *
* do not delete the provisions above, a recipient may use your version of *
* this file under either the SPL or the LGPL. *
* *
* Patrick Niemeyer (pat@pat.net) *
* Author of Learning Java, O'Reilly & Associates *
* http://www.pat.net/~pat/ *
* *
*****************************************************************************/
package bsh;
class
BSHAssignment extends
SimpleNode implements
ParserConstants
{
public int
operator;
BSHAssignment(int
id) { super(
id); }
public
Object eval(
CallStack callstack,
Interpreter interpreter)
throws
EvalError
{
BSHPrimaryExpression lhsNode =
(
BSHPrimaryExpression)
jjtGetChild(0);
if (
lhsNode == null )
throw new
InterpreterError( "Error, null LHSnode" );
boolean
strictJava =
interpreter.
getStrictJava();
LHS lhs =
lhsNode.
toLHS(
callstack,
interpreter);
if (
lhs == null )
throw new
InterpreterError( "Error, null LHS" );
// For operator-assign operations save the lhs value before evaluating
// the rhs. This is correct Java behavior for postfix operations
// e.g. i=1; i+=i++; // should be 2 not 3
Object lhsValue = null;
if (
operator !=
ASSIGN ) // assign doesn't need the pre-value
try {
lhsValue =
lhs.
getValue();
} catch (
UtilEvalError e ) {
throw
e.
toEvalError( this,
callstack );
}
SimpleNode rhsNode = (
SimpleNode)
jjtGetChild(1);
Object rhs;
// implement "blocks" foo = { };
// if ( rhsNode instanceof BSHBlock )
// rsh =
// else
rhs =
rhsNode.
eval(
callstack,
interpreter);
if (
rhs ==
Primitive.
VOID )
throw new
EvalError("Void assignment.", this,
callstack );
try {
switch(
operator)
{
case
ASSIGN:
return
lhs.
assign(
rhs,
strictJava );
case
PLUSASSIGN:
return
lhs.
assign(
operation(
lhsValue,
rhs,
PLUS),
strictJava );
case
MINUSASSIGN:
return
lhs.
assign(
operation(
lhsValue,
rhs,
MINUS),
strictJava );
case
STARASSIGN:
return
lhs.
assign(
operation(
lhsValue,
rhs,
STAR),
strictJava );
case
SLASHASSIGN:
return
lhs.
assign(
operation(
lhsValue,
rhs,
SLASH),
strictJava );
case
ANDASSIGN:
case
ANDASSIGNX:
return
lhs.
assign(
operation(
lhsValue,
rhs,
BIT_AND),
strictJava );
case
ORASSIGN:
case
ORASSIGNX:
return
lhs.
assign(
operation(
lhsValue,
rhs,
BIT_OR),
strictJava );
case
XORASSIGN:
return
lhs.
assign(
operation(
lhsValue,
rhs,
XOR),
strictJava );
case
MODASSIGN:
return
lhs.
assign(
operation(
lhsValue,
rhs,
MOD),
strictJava );
case
LSHIFTASSIGN:
case
LSHIFTASSIGNX:
return
lhs.
assign(
operation(
lhsValue,
rhs,
LSHIFT),
strictJava );
case
RSIGNEDSHIFTASSIGN:
case
RSIGNEDSHIFTASSIGNX:
return
lhs.
assign(
operation(
lhsValue,
rhs,
RSIGNEDSHIFT ),
strictJava );
case
RUNSIGNEDSHIFTASSIGN:
case
RUNSIGNEDSHIFTASSIGNX:
return
lhs.
assign(
operation(
lhsValue,
rhs,
RUNSIGNEDSHIFT),
strictJava );
default:
throw new
InterpreterError(
"unimplemented operator in assignment BSH");
}
} catch (
UtilEvalError e ) {
throw
e.
toEvalError( this,
callstack );
}
}
private
Object operation(
Object lhs,
Object rhs, int
kind )
throws
UtilEvalError
{
/*
Implement String += value;
According to the JLS, value may be anything.
In BeanShell, we'll disallow VOID (undefined) values.
(or should we map them to the empty string?)
*/
if (
lhs instanceof
String &&
rhs !=
Primitive.
VOID ) {
if (
kind !=
PLUS )
throw new
UtilEvalError(
"Use of non + operator with String LHS" );
return (
String)
lhs +
rhs;
}
if (
lhs instanceof
Primitive ||
rhs instanceof
Primitive )
if(
lhs ==
Primitive.
VOID ||
rhs ==
Primitive.
VOID)
throw new
UtilEvalError(
"Illegal use of undefined object or 'void' literal" );
else if (
lhs ==
Primitive.
NULL ||
rhs ==
Primitive.
NULL )
throw new
UtilEvalError(
"Illegal use of null object or 'null' literal" );
if( (
lhs instanceof
Boolean ||
lhs instanceof
Character ||
lhs instanceof
Number ||
lhs instanceof
Primitive) &&
(
rhs instanceof
Boolean ||
rhs instanceof
Character ||
rhs instanceof
Number ||
rhs instanceof
Primitive) )
{
return
Primitive.
binaryOperation(
lhs,
rhs,
kind);
}
throw new
UtilEvalError("Non primitive value in operator: " +
lhs.
getClass() + " " +
tokenImage[
kind] + " " +
rhs.
getClass() );
}
}