Question

有人可以告诉我如何在Common Lisp中内联函数吗？我有很多小的函数，它们总是被调用，因此最好节省这些函数调用的成本。

例如，您如何在“调用者”功能内插入“独立”功能？

(defun standalone ()
 (* 2 5))

(defun caller ()
 (standalone))

Answer 1

(declaim (inline standalone))

(defun standalone ()
 (* 2 5))

(defun caller ()
 (standalone))

文档为here。

（但是请记住，定义一个始终返回数字文字10的函数没有多大意义...）

Answer 2

请参阅食谱：https://lispcookbook.github.io/cl-cookbook/performance.html#code-inline

如果编译器支持，则声明内联将函数调用替换为函数体。这将节省函数调用的成本，但可能会增加代码大小。内联使用的最佳情况可能是那些小的但经常使用的函数。以下代码片段显示了如何鼓励和禁止内联代码。

;; The globally defined function DISPATCH should be open-coded,
;; if the implementation supports inlining, unless a NOTINLINE 
;; declaration overrides this effect.
(declaim (inline dispatch))
(defun dispatch (x) (funcall (get (car x) 'dispatch) x))

;; Here is an example where inlining would be encouraged.
;; Because function DISPATCH was defined as INLINE, the code 
;; inlining will be encouraged by default.
(defun use-dispatch-inline-by-default () 
  (dispatch (read-command)))

;; Here is an example where inlining would be prohibited.
;; The NOTINLINE here only affects this function.
(defun use-dispatch-with-declare-notinline  ()
  (declare (notinline dispatch))
  (dispatch (read-command)))

;; Here is an example where inlining would be prohibited.
;; The NOTINLINE here affects all following code.
(declaim (notinline dispatch))
(defun use-dispatch-with-declaim-noinline () 
  (dispatch (read-command)))

;; Inlining would be encouraged becuase you specified it.
;; The INLINE here only affects this function.
(defun use-dispatch-with-inline () 
  (declare (inline dispatch))
  (dispatch (read-command)))

Answer 3

诸如Allegro CL编译器ignore inline declarations之类的某些实现。

由"details": {创建的

Compiler macros（不同于define-compiler-macro！）也可以用于内联代码。

如何在Common Lisp中内联函数

3 个答案: