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* ~`symbol-function' to get code as list even when byte-compiled?
@ 2015-05-25  2:52 Emanuel Berg
  2015-05-25  2:58 ` Barry Margolin
  2015-05-25  3:10 ` Pascal J. Bourguignon
  0 siblings, 2 replies; 19+ messages in thread
From: Emanuel Berg @ 2015-05-25  2:52 UTC (permalink / raw)
  To: help-gnu-emacs

(re-search-forward "^Question")

Here is some interesting code. What's interesting is:
when this code executes, it changes itself, i.e.
the code changes the code!

But it isn't a macro which is a program that produces
a new program based on its own logic and non-evaluated
input data.

On the contrary, here we deal all with ordinary
functions (defuns) where one changes the other.
Does that always happen? No - only when it is needed!

See the entire code here [1]. Go there if you want to
see this in execution as it probably is based on some
other functions as well. The below code is for display
purposes ONLY!

Question: this is all working thanks to
`symbol-function' which is used to get the code of the
function as data, so it can be examined and
manipulated. However, if I byte-compile the code
(which I always do), `symbol-function' doesn't return
a lambda function which is also a list, but instead
just a function #[...] which isn't a list. So then it
doesn't work!

I was able to do a workaround with `load-file' in
.emacs to get all the functions in the file in
evaluated form. But, can I do that specifically for
a named function, *or*, can I extract the code in list
format somehow even if compiled?

(symbol-function jump)

(defun enable-jump (jump)
  (add-hook 'w3m-display-hook jump)
  (let*((code                  (symbol-function jump))
        (remove-code           `(remove-hook 'w3m-display-hook (quote ,jump)))
        (remove-code-index     2)
        (current-code          (nth remove-code-index code)) )
    (unless (equal current-code remove-code)
      (push remove-code (nthcdr remove-code-index code)) )))

(defun web-search ()
  (interactive)
  (let ((search (get-search-string "Google")))
    (unless (empty-string-p search)
      (w3m-new-tab (format "Google: %s" search))
      (w3m-search w3m-search-default-engine search) ))
  (enable-jump 'number-one-jump) )

(defun number-one-jump (&optional not-used) ; Google, Youtube
  (when (re-search-forward "^ 1." (point-max) t)
    (recenter-top-bottom 0)
    (w3m-next-anchor) ))

[1] http://user.it.uu.se/~embe8573/conf/emacs-init/w3m/w3m-unisearch.el

-- 
underground experts united
http://user.it.uu.se/~embe8573


^ permalink raw reply	[flat|nested] 19+ messages in thread

end of thread, other threads:[~2015-05-27 23:49 UTC | newest]

Thread overview: 19+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2015-05-25  2:52 ~`symbol-function' to get code as list even when byte-compiled? Emanuel Berg
2015-05-25  2:58 ` Barry Margolin
2015-05-25 17:16   ` Emanuel Berg
2015-05-25 17:37     ` Pascal J. Bourguignon
2015-05-25  3:10 ` Pascal J. Bourguignon
2015-05-25 17:07   ` Emanuel Berg
2015-05-25 17:18     ` Pascal J. Bourguignon
     [not found]     ` <mailman.3638.1432574334.904.help-gnu-emacs@gnu.org>
2015-05-25 17:41       ` Emanuel Berg
2015-05-25 17:48         ` Pascal J. Bourguignon
     [not found]         ` <mailman.3640.1432576116.904.help-gnu-emacs@gnu.org>
2015-05-26  0:01           ` Emanuel Berg
2015-05-26  0:12             ` Emanuel Berg
2015-05-26 20:34               ` Stefan Monnier
2015-05-26 23:02                 ` Emanuel Berg
2015-05-27  1:07                   ` Stefan Monnier
2015-05-27  1:31                     ` Emanuel Berg
2015-05-27  1:55                       ` Stefan Monnier
2015-05-27  2:20                         ` Emanuel Berg
2015-05-27  2:31                           ` Stefan Monnier
2015-05-27 23:49                             ` Emanuel Berg

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