From: Michael Heerdegen <michael_heerdegen@web.de>
To: Stefan Monnier <monnier@iro.umontreal.ca>
Cc: Nicolas Petton <nicolas@petton.fr>,
Emacs Development <emacs-devel@gnu.org>
Subject: Re: thunk.el: Document that thunk-force == funcall?
Date: Fri, 27 Nov 2020 18:22:38 +0100 [thread overview]
Message-ID: <87im9qhfz5.fsf@web.de> (raw)
In-Reply-To: <87v9dtttbr.fsf@web.de> (Michael Heerdegen's message of "Wed, 25 Nov 2020 15:16:40 +0100")
Michael Heerdegen <michael_heerdegen@web.de> writes:
> I don't have any concrete real-life examples. [...]
Actually I have one real-life example:
#+begin_src emacs-lisp
(defun el-search--change-p (posn revision)
;; Non-nil when sexp after POSN is part of a change
(if (buffer-modified-p)
(if (eq this-command 'el-search-pattern)
(user-error "Buffer is modified - please save")
nil)
(save-restriction
(widen)
(let ((changes (el-search--changes-from-diff-hl revision))
(sexp-end (el-search--end-of-sexp posn))
(atomic? (thunk-delay (el-search--atomic-p
(save-excursion (goto-char posn)
(el-search-read (current-buffer)))))))
(while (and changes (or (< (cdar changes) posn)
(and
;; a string spanning multiple lines is a change even when not all
;; lines are changed
(< (cdar changes) sexp-end)
(not (thunk-force atomic?)))))
(pop changes))
(and changes (or (<= (caar changes) posn)
(and (thunk-force atomic?)
(<= (caar changes) sexp-end))))))))
#+end_src
I can live with `thunk-force' here; being able to use it as a function
would make the code a bit more readable. Although, hiding the
function's nature as a thunk might not be good OTOH.
A thunk or fbound function have the advantage that they can be passed
without forcing. Contrary to symbols bound with `thunk-let'; a thunk
passed to a function this way is forced before that function is called,
even when the thunk's result is never used. That's why I'm wondering
whether `thunk-let' is as cool as I had thought.
Ok, anything else to say, apart from the empty string?
Regards,
Michael.
next prev parent reply other threads:[~2020-11-27 17:22 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-17 15:17 thunk.el: Document that thunk-force == funcall? Michael Heerdegen
2020-11-17 17:08 ` Tomas Hlavaty
2020-11-17 17:38 ` Michael Heerdegen
2020-11-17 18:09 ` Tomas Hlavaty
2020-11-17 21:07 ` Michael Heerdegen
2020-11-17 22:42 ` Tomas Hlavaty
2020-11-17 23:52 ` Stefan Monnier
2020-11-18 8:01 ` Tomas Hlavaty
2020-11-18 14:04 ` Stefan Monnier
2020-11-18 22:19 ` Tomas Hlavaty
2020-11-18 22:49 ` Stefan Monnier
2020-11-18 23:13 ` Tomas Hlavaty
2020-11-18 23:40 ` Stephen Leake
2020-11-18 9:04 ` Alfred M. Szmidt
2020-11-18 22:21 ` Tomas Hlavaty
2020-11-17 17:32 ` Drew Adams
2020-11-18 23:05 ` Tomas Hlavaty
2020-11-18 23:25 ` Tomas Hlavaty
2020-11-19 11:50 ` Mattias Engdegård
2020-11-19 18:14 ` Tomas Hlavaty
2020-11-19 17:18 ` Tomas Hlavaty
2020-11-19 9:49 ` Nicolas Petton
2020-11-17 21:51 ` Stefan Monnier
2020-11-25 14:16 ` Michael Heerdegen
2020-11-27 17:22 ` Michael Heerdegen [this message]
2020-12-17 4:37 ` Michael Heerdegen
2020-12-18 2:58 ` Adam Porter
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