Inheritance: CodeObject
 ScriptObject ParseEval(CodeEval eval)
 {
     ScriptString obj = ResolveOperand(eval.EvalObject) as ScriptString;
     if (obj == null) throw new ExecutionException(m_script, "Eval参数必须是一个字符串");
     return m_script.LoadString("", obj.Value, this, false);
 }
 //返回执行一段字符串
 private CodeEval GetEval()
 {
     CodeEval ret = new CodeEval();
     ret.EvalObject = GetObject();
     return ret;
 }