/jEdit/tags/jedit-4-5-pre1/org/gjt/sp/jedit/bsh/BSHPrimaryExpression.java

  1/*****************************************************************************
  2 *                                                                           *
  3 *  This file is part of the BeanShell Java Scripting distribution.          *
  4 *  Documentation and updates may be found at http://www.beanshell.org/      *
  5 *                                                                           *
  6 *  Sun Public License Notice:                                               *
  7 *                                                                           *
  8 *  The contents of this file are subject to the Sun Public License Version  *
  9 *  1.0 (the "License"); you may not use this file except in compliance with *
 10 *  the License. A copy of the License is available at http://www.sun.com    * 
 11 *                                                                           *
 12 *  The Original Code is BeanShell. The Initial Developer of the Original    *
 13 *  Code is Pat Niemeyer. Portions created by Pat Niemeyer are Copyright     *
 14 *  (C) 2000.  All Rights Reserved.                                          *
 15 *                                                                           *
 16 *  GNU Public License Notice:                                               *
 17 *                                                                           *
 18 *  Alternatively, the contents of this file may be used under the terms of  *
 19 *  the GNU Lesser General Public License (the "LGPL"), in which case the    *
 20 *  provisions of LGPL are applicable instead of those above. If you wish to *
 21 *  allow use of your version of this file only under the  terms of the LGPL *
 22 *  and not to allow others to use your version of this file under the SPL,  *
 23 *  indicate your decision by deleting the provisions above and replace      *
 24 *  them with the notice and other provisions required by the LGPL.  If you  *
 25 *  do not delete the provisions above, a recipient may use your version of  *
 26 *  this file under either the SPL or the LGPL.                              *
 27 *                                                                           *
 28 *  Patrick Niemeyer (pat@pat.net)                                           *
 29 *  Author of Learning Java, O'Reilly & Associates                           *
 30 *  http://www.pat.net/~pat/                                                 *
 31 *                                                                           *
 32 *****************************************************************************/
 33
 34
 35package org.gjt.sp.jedit.bsh;
 36
 37class BSHPrimaryExpression extends SimpleNode
 38{
 39	BSHPrimaryExpression(int id) { super(id); }
 40
 41	/**
 42		Evaluate to a value object.
 43	*/
 44	public Object eval( CallStack callstack, Interpreter interpreter)  
 45		throws EvalError
 46	{
 47		return eval( false, callstack, interpreter );
 48	}
 49
 50	/**
 51		Evaluate to a value object.
 52	*/
 53	public LHS toLHS( CallStack callstack, Interpreter interpreter)  
 54		throws EvalError
 55	{
 56		Object obj = eval( true, callstack, interpreter );
 57
 58		if ( ! (obj instanceof LHS) )
 59			throw new EvalError("Can't assign to:", this, callstack );
 60		else
 61			return (LHS)obj;
 62	}
 63
 64	/*
 65		Our children are a prefix expression and any number of suffixes.
 66		<p>
 67
 68		We don't eval() any nodes until the suffixes have had an
 69		opportunity to work through them.  This lets the suffixes decide
 70		how to interpret an ambiguous name (e.g. for the .class operation).
 71	*/
 72	private Object eval( boolean toLHS, 
 73		CallStack callstack, Interpreter interpreter)  
 74		throws EvalError
 75	{
 76		Object obj = jjtGetChild(0);
 77		int numChildren = jjtGetNumChildren(); 
 78
 79		for(int i=1; i<numChildren; i++)
 80			obj = ((BSHPrimarySuffix)jjtGetChild(i)).doSuffix(
 81				obj, toLHS, callstack, interpreter);
 82
 83		/*
 84			If the result is a Node eval() it to an object or LHS
 85			(as determined by toLHS)
 86		*/
 87		if ( obj instanceof SimpleNode )
 88			if ( obj instanceof BSHAmbiguousName )
 89				if ( toLHS )
 90					obj = ((BSHAmbiguousName)obj).toLHS(
 91						callstack, interpreter);
 92				else
 93					obj = ((BSHAmbiguousName)obj).toObject(
 94						callstack, interpreter);
 95			else 
 96				// Some arbitrary kind of node
 97				if ( toLHS )
 98					// is this right?
 99					throw new EvalError("Can't assign to prefix.", 
100						this, callstack );
101				else
102					obj = ((SimpleNode)obj).eval(callstack, interpreter);	
103
104		// return LHS or value object as determined by toLHS
105		if ( obj instanceof LHS )
106			if ( toLHS )
107				return obj;
108			else
109				try {
110					return ((LHS)obj).getValue();
111				} catch ( UtilEvalError e ) {
112					throw e.toEvalError( this, callstack );
113				}
114		else
115			return obj;
116	}
117}
118