如何编程检查读取器宏 [英] how to programatically check for reader macros

问题描述

我有一个可以包含任意数据的向量。我想检查任何元素是一个读者宏，我该如何做？

（is-reader-macro？ ; DateTime 2012>）; => true

解决方案

一旦字符串读取，你不能通过结果数据来确定读取器结构是创建它。您刚刚读取的数据项不是阅读器宏，而只是数据。

在您的具体示例中，您所获得的是jodatime DateTime对象的打印表示，其不能被读取 - ＃< ...> 构造是为了防止这种情况。打印的实际对象只是一个jodatime DateTime对象，而不是阅读器宏。

I have a vector which can contain arbitrary data. I want to check of any of the element is a reader macro, how do I do that ?

(is-reader-macro? #<DateTime 2012>) ;=> true

Thanks, Murtaza

解决方案

Once a string is read you cannot tell by the resulting data what the exact reader construct was that created it. The data item you just read is not a reader macro, it's just data.

In your specific example, what you've got is the printed representation of a jodatime DateTime object, which cannot be read - the #< ... > construct is meant to prevent that. The actual object that prints like that is just a jodatime DateTime object, not a reader macro.

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