From: "Andreas Röhler" <andreas.roehler@online.de>
To: "Stephen J. Turnbull" <stephen@xemacs.org>
Cc: Andreas Schwab <schwab@linux-m68k.org>,
Emacs developers <emacs-devel@gnu.org>
Subject: Re: forward-paragraph return value
Date: Tue, 24 Aug 2010 11:14:21 +0200 [thread overview]
Message-ID: <4C738D6D.5040805@online.de> (raw)
In-Reply-To: <87y6bw5sb8.fsf@uwakimon.sk.tsukuba.ac.jp>
Am 24.08.2010 10:27, schrieb Stephen J. Turnbull:
> Andreas Röhler writes:
>
> > Then people may write functions taking already the return value.
>
> Sure. But will they? Show us examples of existing functions
> (preferably already in Emacs) that would benefit from this change.
>
Didn't I point to?
If a look in forward-paragraph doesn't speak to you,
maybe have a look into
bounds-of-thing-at-point .
Forms like
(let
(beg
(progn
(funcall
(or (get thing 'beginning-op)
(lambda () (forward-thing thing -1))))
(point))))
Thats bug-sourcing BTW, as it returns point in any case, even if move
failed.
Why not make implementation of return value from
search-forward
canonical instead, returning the position if succesful, nil otherwise.
The gain will be for newly written code.
For writers first, who must not learn function by function the return value.
In the example above we could write
(let
(beg
(funcall
(or (get thing 'beginning-op)
(lambda () (forward-thing thing -1))))))
Its clean and much more reliable, as beg will be nil, if nothing was found.
> An easy example would be functions which look like
>
> ;; some code here
> (forward-paragraph count)
> (foo (point) other args)
> ;; more code
>
> But it's not clear to me that
>
> ;; some code here
> (foo (forward-paragraph count) other args)
> ;; more code
>
> is going to be more readable without seeing examples. Since point has
> a byte code, it's not particularly costly to use point.
>
>
next prev parent reply other threads:[~2010-08-24 9:14 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-23 18:25 forward-paragraph return value Andreas Röhler
2010-08-23 20:59 ` Andreas Schwab
2010-08-24 5:43 ` Andreas Röhler
2010-08-24 8:27 ` Stephen J. Turnbull
2010-08-24 9:14 ` Andreas Röhler [this message]
2010-08-24 11:30 ` Davis Herring
2010-08-24 16:57 ` Andreas Röhler
2010-08-24 12:06 ` Stephen J. Turnbull
2010-08-24 17:10 ` Andreas Röhler
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