From: rm@fabula.de
Cc: Marius Vollmer <mvo@zagadka.ping.de>,
ttn@glug.org, rlb@defaultvalue.org, guile-devel@gnu.org,
guile-user@gnu.org
Subject: Re: Items blocking release 1.6.1 (2002-04-21)
Date: Thu, 25 Apr 2002 12:02:54 +0200 [thread overview]
Message-ID: <20020425100254.GC19024@www> (raw)
In-Reply-To: <20020425090914.GA19031@www>
On Thu, Apr 25, 2002 at 11:09:14AM +0200, tomas@fabula.de wrote:
> On Tue, Apr 23, 2002 at 08:16:20PM +0200, Marius Vollmer wrote:
> [...]
> > Yes. The way the old 'bound?' was implemented was a bug. The mistake
> > (my mistake) back then was to fix this bug in a sub-optimal way, by
> > just removing the functionality. Now it is too late to change it
> > again; and changing it would be quite gratuitous, too.
> >
> > Using #f as the default default value is a sensible thing, I'd say,
> > and should even be recommended.
>
> As a provider of some functionality I'd sometimes like to be able
> to distinguish between `value was provided' and `value was not
> provided at all'. It'd be perfectly reasonable to agree on a
> value which means `not provided' (like Perl's undef or Pythons
> None): an user providing *such* a value hopefully knows what
> she's doing...
>
> > From a robustness standpoint,
> > distinguishing between explicitely specifying a keyword with its
> > default value in a function call, and not specifying it, should not be
> > done. That is, it is better to say "When you don't specify the :foo
> > keyword, it's value is defaulted to #f. A value of #f means bla."
> > instead of "When you don't specify the :foo keyword, it means bla."
I'd like to second Tomas here. Default values are essential for some
applications (esp. if guile want's to be used as a scripting language).
I don't want to force my users to have to specify all possible keywords
and i can well imagine that i need to have keywords with boolean values:
(read-text :convert-newline #f) =/= (read-text)
(foo-create-window ) =?= (foo-create-window :map #f)
>
> (BTW. I just resisted the temptation to propose '(), because
> that's quite another thread ;->
... not to mention NIL :-)
Thanks
ralf
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next prev parent reply other threads:[~2002-04-25 10:02 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-04-22 20:05 Items blocking release 1.6.1 (2002-04-21) Thien-Thi Nguyen
2002-04-22 20:15 ` Rob Browning
2002-04-22 20:52 ` Thien-Thi Nguyen
2002-04-22 21:12 ` Rob Browning
2002-04-22 21:25 ` Rob Browning
2002-04-22 21:30 ` Rob Browning
2002-04-22 21:51 ` Thien-Thi Nguyen
2002-04-22 23:03 ` Rob Browning
2002-04-22 20:29 ` Bill Gribble
2002-04-22 21:20 ` Thien-Thi Nguyen
2002-04-23 18:16 ` Marius Vollmer
2002-04-25 9:09 ` tomas
2002-04-25 10:02 ` rm [this message]
2002-04-28 16:00 ` Marius Vollmer
2002-04-28 20:27 ` Thien-Thi Nguyen
2002-05-07 18:43 ` Marius Vollmer
2002-04-28 15:58 ` Marius Vollmer
2002-04-28 20:38 ` spu
-- strict thread matches above, loose matches on Subject: below --
2002-04-21 16:22 Rob Browning
2002-04-22 8:35 ` Thien-Thi Nguyen
2002-04-22 13:02 ` Rob Browning
2002-04-22 18:04 ` Marius Vollmer
2002-04-22 18:26 ` Rob Browning
2002-04-22 18:44 ` Marius Vollmer
2002-04-22 18:56 ` Rob Browning
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