Bug 183733 Implement the IScriptOjectClassInfo to provide the class infromation to support the JS code assistant.
Engine should implement the IScriptObjectClassInfo interface to return the class information for script object.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/executor/ExecutionContext.java
return scriptContext.eval( expr, name, lineNo );
			}
			catch ( Throwable e )
			{
				log.log( Level.SEVERE, e.getMessage( ), e );
				addException( new EngineException(
						MessageConstants.SCRIPT_EVALUATION_ERROR, expr, e ) ); 
			}
		}
		return null;
	}	
	/**
	 * evaluate conditional expression. A conditional expression can have an
	 * operator, one LHS expression, and up to two expressions on RHS, i.e.,
	 * 
	 * testExpr operator operand1 operand2 or testExpr between 1 20
	 * 
	 * Now only support comparison between the same data type
	 * 
	 * @param expr
	 *            the conditional expression to be evaluated
	 * @return a boolean value (as an Object)
	 */
	public Object evaluateCondExpr( IConditionalExpression expr )
	{
		int operator = expr.getOperator( );
		IScriptExpression testExpr = expr.getExpression( );
		IScriptExpression v1 = expr.getOperand1( );
		IScriptExpression v2 = expr.getOperand2( );
		if ( testExpr == null )