在宏中使用循环

Question

考虑这个最小的例子

(defmacro foo []
  `(list ,@(for [i [1 2 3]] (+ 1 i))))

我希望 (foo) 扩展到 (list 2 3 4)

但是，当我尝试 (macroexpand-1 (foo)

时，我遇到了一堆无法辨认的错误

Syntax error macroexpanding clojure.core/let at (*cider-repl <filepath>:localhost:43203(clj)*:366:22).
test/i - failed: simple-symbol? at: [:bindings :form :local-symbol] spec: :clojure.core.specs.alpha/local-name
test/i - failed: vector? at: [:bindings :form :seq-destructure] spec: :clojure.core.specs.alpha/seq-binding-form
test/i - failed: map? at: [:bindings :form :map-destructure] spec: :clojure.core.specs.alpha/map-bindings
test/i - failed: map? at: [:bindings :form :map-destructure] spec: :clojure.core.specs.alpha/map-special-binding

怎么了？我不能在宏定义中使用 for 循环吗？

Answer 1

,@ 应该是 ~@.

user=> (defmacro foo []
  `(list ~@(for [i [1 2 3]] (+ 1 i))))
#'user/foo

user=> (macroexpand-1 '(foo))
(clojure.core/list 2 3 4)

user=> (foo)
(2 3 4)

在宏中使用循环

Using a loop inside a macro

clojure