/// <summary>
/// 计算表达式
/// </summary>
/// <param name="polish">表达式的逆波兰式</param>
/// <param name="vsm">关于哪个调用堆栈做动作</param>
/// <returns>计算结果的值（Double/字符串）</returns>
public static object Evaluate(string polish, StackMachine vsm)
{
var calcList = PolishEvaluator.GetPolishItemList(polish, vsm, null);
return(PolishEvaluator.HandleEval(polish, calcList));
}
/// <summary>
/// 计算表达式的值
/// </summary>
/// <param name="expr">表达式字符串</param>
/// <param name="ctx">求值上下文</param>
/// <returns>计算结果的值（Double/字符串）</returns>
public object Eval(string expr, EvaluatableContext ctx)
{
var calcList = PolishEvaluator.GetPolishItemList(expr, null, ctx);
return(PolishEvaluator.HandleEval(expr, calcList));
}
