From: Eric Schulte <schulte.eric@gmail.com>
To: Tassilo Horn <tassilo@member.fsf.org>
Cc: emacs-orgmode@gnu.org
Subject: Re: Elisp programming style
Date: Fri, 28 Oct 2011 08:40:29 -0600 [thread overview]
Message-ID: <877h3puqle.fsf@gmail.com> (raw)
In-Reply-To: <87fwiddw1l.fsf@thinkpad.tsdh.de> (Tassilo Horn's message of "Fri, 28 Oct 2011 16:34:46 +0200")
Tassilo Horn <tassilo@member.fsf.org> writes:
> Thorsten <quintfall@googlemail.com> writes:
>
>>> Too bad you didn't give any concrete examples.
>>
>> The problem can be described easily:
>>
>> problem-specific helper-funcions (some redundancy avoided)
>> ,-----------------------------------------------------------
>> | (defun main-function (args)
>> | (let ((var (assoc :key1 args))) ; extracting var once
>> | ...
>> | (helper-function1 ...) ; inside let using var
>> | (helper-function2 ...) ; inside let using var
>> | ))
>> |
>> | (defun helper-function1 ()
>> | ...
>> | )
>> |
>> | (defun helper-function2 ()
>> | ...
>> | )
>> `-----------------------------------------------------------
>>
>> vs
>>
>> standalone helper-functions (but redundancy)
>> ,-------------------------------------------------------------
>> | (defun main-function (args)
>> | (let ((value (assoc :key1 args)) ; extracting var 1st time
>> | ...
>> | )
>> | (helper-function1 ...) ; outside let
>> | (helper-function2 ...) ; outside let
>> | )
>> |
>> | (defun helper-function1 (args)
>> | (let ((var (assoc :key1 args))) ; extracting var 2nd time
>> | ...
>> | ))
>> |
>> | (defun helper-function2 (args)
>> | (let ((var (assoc :key1 args))) ; extracting var 3rd time
>> | ...
>> | ))
>> `-------------------------------------------------------------
>
> That's still very vague. If `args' is some structure that has some
> meaning and its parts belong together, say, an org entry, then it makes
> sense to have the helper functions defined on that structure in order to
> provide a consistent interface throughout the library. And I wouldn't
> tell multiple similar let-bindings duplicate code.
>
To clarify my earlier reply, I would agree with Tassilo above. If args
is a global variable (declared with defvar or defconst) then using it
without accepting it as an argument is not a problem (and the emacs-lisp
compiler will not complain).
Best -- Eric
--
Eric Schulte
http://cs.unm.edu/~eschulte/
next prev parent reply other threads:[~2011-10-28 14:40 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 [this message]
2011-10-28 16:04 ` Thorsten
2011-10-28 14:35 ` Eric Schulte
2011-10-28 15:52 ` Thorsten
2011-10-28 17:43 ` Tom Prince
2011-10-28 18:05 ` Thorsten
2011-10-29 7:43 ` Tassilo Horn
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