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December 11, 2018 12:50
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自制@裝飾器
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(defun Decorators (stream ch1) | |
(declare (ignore ch1)) | |
(let ((Decorator (read stream)) | |
(the-func-form (read stream))) | |
(unless (eq (first the-func-form) 'defun) | |
(error "need 'defun")) | |
(let ((the-func-name (second the-func-form)) | |
(the-func-args (third the-func-form)) | |
(the-func (cdddr the-func-form))) | |
`(flet ((old-func ,the-func-args ,@the-func)) | |
(defun ,the-func-name ,the-func-args | |
(funcall (,Decorator #'old-func) ,@the-func-args)))))) | |
(defun print-hello (func) | |
(print 'hello) | |
func) | |
(defun hello-name (name) | |
(format t "~&Hello, ~A~%" name)) | |
(hello-name "john") | |
(funcall (print-hello #'hello-name) "john") | |
(set-macro-character #\@ | |
#'Decorators) | |
@print-hello | |
(defun hello-world () | |
(format t "~&Hello, world~%")) | |
#| output the result | |
(print (with-input-from-string (s "print-hello | |
(defun hello-world () | |
(format t \"~&Hello, world~%\"))") | |
(Decorators s #\@))) | |
|# | |
(hello-world) | |
@print-hello | |
(defun show-num (num) | |
(print num)) | |
(show-num 10) | |
#| | |
(print (with-input-from-string (s "print-hello | |
(defun show-num (num) | |
(print num))") | |
(Decorators s #\@))) | |
|# |
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