正则表达式在Emacs中搜索不是以分号开头的行

Question

I am trying to search forward in the current buffer for the first elisp function definition that is not a comment. I tried this:

(re-search-forward "[^;] *\(defun ")

but it matches comments anyway. Like the following line:

;; (defun test ()

Answer 1

You can use:

 (catch 'found
  (let (match)
    (while (setq match (search-forward "(defun "))
      (when (null (syntax-ppss-context (syntax-ppss)))
        (throw 'found match)))
    nil))

It relies on the internal parser and the language syntax definition. It returns only the result of search-forward if point is not in a comment and not in a string. If you do not like the error in the case of a search without hits you can add nil t to the arguments of the search-forward command. Search with re-search-forward is also fine.

This also works for cases like:

(defun test (args)
  "This function is defined with (defun test (args) ...)"
  )

Answer 2

(defun test ()的空格实际上与[^;]匹配。由于您具有* ，因此不需要另一个空格。您可能需要使用[^;] + 。但是，可以在

\(?<!;;)

Answer 3

This seems to work nicely for me (tested in *scratch*):

(re-search-forward "^ *\(defun " nil t) ; hit C-x C-e after that
                                        ; closing parenthesis

;; (defun hi () )
(defun hola () )