Re: Closures in Emacs and their usage scenarios.

[Emanuel Berg]

> (let ((alf-regexp))
>   (defun align-from-left (&optional set-regexp)
>     (interactive "p")
>     (let ((default-regexp "^\\|[[:punct:]]\\|[[:space:]][[:alnum:]]"))
>       (unless (stringp set-regexp)
>         (cl-case set-regexp
>           ( 4 (setq alf-regexp (read-regexp "regexp: ")))
>           (16 (setq alf-regexp default-regexp))
>           ( t (unless alf-regexp
>                 (setq alf-regexp default-regexp) )))))
>     (let ((beg (point))
>           (re  (or (and (stringp set-regexp) set-regexp)
>                     alf-regexp) ))
>       (when (re-search-backward re (line-beginning-position) t)
>         (while (looking-at "[[:space:]]")
>           (forward-char 1) )
>         (insert (make-string (- beg (point)) ?\s)) ))))

Hm, looking at the code now I don't really understand what
that regular expression

  "^\\|[[:punct:]]\\|[[:space:]][[:alnum:]]"

is supposed to say ... but the program seems to work as
intended.

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