传递给宏的变量在错误的命名空间中解析？ [英] Variable passed to macro gets resolved in wrong namespace?

问题描述

Noir 宏 defpage 给我一些麻烦。我试图构造一个类似于这样的调用：

The Noir macro defpage is giving me a little bit of trouble. I am trying to construct a call similar to this:

(defpage [:post "some/url"] [data]
  ;; some stuff...
  )

关键字：post 我想使用一个变量，如下所示：

However, instead of using the keyword :post I would like to use a variable, like this:

(def my-method :post)
(defpage [my-method "some/url"] [data]
  ;; some stuff...
  )

$ b < c $ c>在 compojure.core 命名空间而不是我自己的，给我错误：

The problem is that when the macro expands, it wants to resolve the variable my-method in the compojure.core namespace instead of my own, giving me the error:

No such var: compojure.core/MY-METHOD

推荐答案

我在方法猜猜这是一个类似的问题：如何将clojure的doc函数应用于一系列函数
宏可以使用其args做任何想要的操作，因此传递裸体符号可能导致不可预测的结果。

I guess this is a similar problem to: How can I apply clojure's doc function to a sequence of functions A macro can do whatever it wants with its args, so passing a naked symbol in can result in unpredictable results.

一种解决方法，但它不漂亮：

A way to solve it, but it ain't pretty:

(eval (list 'defpage (vector my-method "some/url") '[data]
  ; some stuff
))

请注意，my-method不是一个文字，在进入eval之前首先在我们自己的命名空间中解析和求值。

Notice that my-method is not a literal here, so it gets resolved and evaluated in our own namespace first, before going into eval.

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