From: Oleh Krehel <ohwoeowho@gmail.com>
To: emacs-devel@gnu.org
Cc: monnier@iro.umontreal.ca
Subject: Question on pcase
Date: Thu, 22 Oct 2015 16:46:41 +0200 [thread overview]
Message-ID: <871tcngdv2.fsf@gmail.com> (raw)
To be frank, I'm not a fan of `pcase', and really prefer a "for dummies"
coding style. But if it makes other people feel more productive, I'm
fine with it as long as I can read and debug it.
One piece that I'm missing currently is the ability to eval a `pcase'
pattern. To explain what I mean, here's a function that I was debugging
just now:
(defun completion-at-point ()
"Perform completion on the text around point.
The completion method is determined by `completion-at-point-functions'."
(interactive)
(let ((res (run-hook-wrapped 'completion-at-point-functions
#'completion--capf-wrapper 'all)))
(pcase res
(`(,_ . ,(and (pred functionp) f)) (funcall f))
(`(,hookfun . (,start ,end ,collection . ,plist))
(unless (markerp start) (setq start (copy-marker start)))
(let* ((completion-extra-properties plist)
(completion-in-region-mode-predicate
(lambda ()
;; We're still in the same completion field.
(let ((newstart (car-safe (funcall hookfun))))
(and newstart (= newstart start))))))
(completion-in-region start end collection
(plist-get plist :predicate))))
;; Maybe completion already happened and the function returned t.
(_
(when (cdr res)
(message "Warning: %S failed to return valid completion data!"
(car res)))
(cdr res)))))
I have `res' stored in a global variable and would like to know which
branch will match, and store e.g. `hookfn' etc in global variables as
well.
What I want is an interface that allows me to position the point like
this (just so it's clear which branch I've selected):
|(`(,hookfun . (,start ,end ,collection . ,plist))
and press something akin to "C-x C-e" that either says "The pattern did
not match", or evaluates:
(progn
(setq hook-fn (car res))
(setq rest (cdr res))
(setq start (nth 0 (cdr res)))
(setq end (nth 1 (cdr res)))
(setq collection (nth 2 (cdr res)))
(setq plist (nthcdr 3 (cdr res))))
The single function that I need is basically:
(should (equal
(pcase--expand-if-match
'(,hookfun . (,start ,end ,collection . ,plist))
'res)
'(progn
(setq hookfun (car res))
(setq start (nth 0 (cdr res)))
(setq end (nth 1 (cdr res)))
(setq collection (nth 2 (cdr res)))
(setq plist (nthcdr 3 (cdr res))))))
Could someone please help me to implement `pcase--expand-if-match'. I
think it should be trivial to do for a person that understands how
`pcase' works. I don't want to learn how to write `pcase', but the above
functionality would be more than enough for me to be able to read and
edit its inner contents.
thanks in advance,
Oleh
next reply other threads:[~2015-10-22 14:46 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-22 14:46 Oleh Krehel [this message]
2015-10-22 21:19 ` Question on pcase Michael Heerdegen
2015-10-23 6:30 ` Eli Zaretskii
2015-10-23 11:58 ` Oleh Krehel
2015-10-23 12:23 ` Michael Heerdegen
2015-10-23 12:42 ` Oleh Krehel
2015-10-23 13:07 ` Michael Heerdegen
2015-10-23 13:26 ` Oleh Krehel
2015-10-23 13:59 ` Michael Heerdegen
2015-10-27 23:50 ` Johan Bockgård
2015-10-30 1:33 ` Michael Heerdegen
2015-10-23 14:23 ` Michael Heerdegen
2015-10-23 12:17 ` Michael Heerdegen
2015-10-23 12:22 ` Oleh Krehel
2015-10-23 13:26 ` Eli Zaretskii
2015-10-23 14:14 ` Michael Heerdegen
2015-10-23 14:41 ` Eli Zaretskii
2015-10-23 18:38 ` Michael Heerdegen
2015-10-23 18:43 ` Eli Zaretskii
2015-10-23 19:59 ` Przemysław Wojnowski
2015-10-23 21:01 ` Michael Heerdegen
2015-10-23 20:23 ` Przemysław Wojnowski
2015-10-23 20:39 ` Michael Heerdegen
2015-10-24 11:37 ` Przemysław Wojnowski
2015-10-24 9:01 ` Alan Mackenzie
2015-10-24 12:58 ` Stephen Berman
2015-10-24 17:47 ` Alan Mackenzie
2015-10-24 19:10 ` Stephen Berman
2015-10-24 19:28 ` Alan Mackenzie
2015-10-25 0:00 ` pcase docstring tweaks (was: Question on pcase) Michael Heerdegen
2015-10-27 14:54 ` pcase docstring tweaks Michael Heerdegen
2015-10-27 18:57 ` Stefan Monnier
2015-10-27 20:14 ` Michael Heerdegen
2015-10-28 3:15 ` Richard Stallman
2015-10-28 17:08 ` Michael Heerdegen
2015-10-24 17:00 ` Question on pcase Drew Adams
2015-10-24 17:22 ` Alan Mackenzie
2015-10-24 17:36 ` Drew Adams
2015-10-24 20:03 ` Johan Bockgård
2015-10-24 23:11 ` Michael Heerdegen
2015-10-26 15:55 ` Oleh Krehel
2015-10-26 16:07 ` Michael Heerdegen
2015-10-27 8:42 ` Oleh Krehel
2015-10-26 16:20 ` Michael Heerdegen
2015-10-27 8:42 ` Oleh Krehel
2015-10-27 14:27 ` Michael Heerdegen
2015-10-27 14:47 ` Michael Heerdegen
2015-10-28 18:05 ` Michael Heerdegen
2015-10-29 9:44 ` Oleh Krehel
2015-10-30 1:11 ` Michael Heerdegen
2015-10-26 16:35 ` Andreas Schwab
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=871tcngdv2.fsf@gmail.com \
--to=ohwoeowho@gmail.com \
--cc=emacs-devel@gnu.org \
--cc=monnier@iro.umontreal.ca \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this external index
https://git.savannah.gnu.org/cgit/emacs.git
https://git.savannah.gnu.org/cgit/emacs/org-mode.git
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.