From: Thorsten <quintfall@googlemail.com>
To: emacs-orgmode@gnu.org
Subject: Re: Elisp programming style
Date: Fri, 28 Oct 2011 17:52:41 +0200 [thread overview]
Message-ID: <86k47pqfjq.fsf@googlemail.com> (raw)
In-Reply-To: 87fwiduqti.fsf@gmail.com
Eric Schulte <schulte.eric@gmail.com> writes:
Hi Eric,
> Hmmm, this looks suspiciously like the case in some Babel functions :)
well ... ;)
> in which we originally has instances of the first style and then had to
> manually transition to the second. IMO the first is very poor form, the
> variables are technically "free variables" when defined in the helper,
> and just through undocumented variable capture does the execution work
> out correctly, this can lead to unpleasant bugs.
>
> The means the helper may only be used when variables of certain names
> are in scope.
>
> If you do want to use a helper which uses variables in scope which
> aren't passed as arguments (again just my opinion) you should defined
> the helper function using `flet' *inside* of the main function and the
> scope of the variables.
That sounds like an operational prescription to me, and I think will
follow this advice in the future.
>> Would that be considered bad style from the original author, or is that
>> up to personal choice and not considered a problem?
>>
>
> I don't believe we have an official canon of such rules, but personally
> I would consider this to be bad style. If the helper function is only
> used in one main function then it should be defined using flet, if it is
> used across multiple functions then the in-scope variables should be
> passed as explicit arguments (preferably with names other than those
> which it has in scope so you can be sure you are actually using the
> arguments).
>
> Finally, I believe the emacs-lisp compiler would complain about such
> free variables.
>
> Hope this helps, Best -- Eric
yes that helped, thanks
cheers
--
Thorsten
next prev parent reply other threads:[~2011-10-28 15:53 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-27 18:03 Elisp programming style Thorsten
2011-10-28 10:17 ` Štěpán Němec
2011-10-28 14:09 ` Thorsten
2011-10-28 14:31 ` Nick Dokos
2011-10-28 15:59 ` Thorsten
2011-10-29 2:13 ` Eric Abrahamsen
2011-10-28 14:34 ` Tassilo Horn
2011-10-28 14:40 ` Eric Schulte
2011-10-28 16:04 ` Thorsten
2011-10-28 14:35 ` Eric Schulte
2011-10-28 15:52 ` Thorsten [this message]
2011-10-28 17:43 ` Tom Prince
2011-10-28 18:05 ` Thorsten
2011-10-29 7:43 ` Tassilo Horn
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