将列表散布到父项sexp中 [英] Spread a list into parent sexp

问题描述

在任何Lisp中是否存在可以传播"父sexp中的列表的表单?喜欢:

Is there a form in any lisp that could "spread" a list in the parent sexp? Like:

(+ (spread '(1 2 3))) -> (+ 1 2 3)

推荐答案

有两种方法.哪个更好取决于最终想要的东西.

There are two way to do it. Which is better depends on what you want in the end.

通常，您可以在`(反引号)内使用,@.计算,@之后的形式以生成列表，然后将其拼接到模板中:

Generally, you can use ,@ inside ` (backquote). The form following ,@ is evaluated to produce a list, which is then spliced into the template:

* `(+ ,@'(1 2 3))
(+ 1 2 3)

* (eval `(+ ,@'(1 2 3)))
6

或者，如果您只想使用包装在列表中的参数来调用函数，则使用apply函数将更加方便:

Or, if you just want to call a function with its arguments which are packed in a list, it will be more convenient to use the apply function:

* (apply #'+ '(1 2 3))
6

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