Re: [Chicken-hackers] [PATCH] Allow optional functor arguments

[Felix Winkelmann]

From: Peter Bex <address@hidden>
Subject: Re: [Chicken-hackers] [PATCH] Allow optional functor arguments
Date: Sat, 12 Jul 2014 18:04:51 +0200

> On Mon, Jul 07, 2014 at 10:46:47PM +0200, Felix Winkelmann wrote:
>> Hello!
>> 
>> Here another (and proper) patch: it allows functor arguments to be
>> optional, giving the author or a functor a way to provide a default,
>> which seems to be quite useful. I think this patch was submitted
>> before, but seems to have been forgotten.
> 
> Hi Felix!
> 
> Thanks for re-submitting it.  I think it was only posted to our Trac
> installation as #1121, but that doesn't matter much.
> 
>> This patch also fixes a bug in the functor-argument matching code:
>> when verifying whether a module given as argument exports the required
>> binding, the export-list was previously checked (that's the list given
>> in a module declaration, specifying the exports). But that was
>> incorrect, as, for example, builtin modules (like "scheme") do not
>> have export lists. This change uses the "vexports"/"sexports" lists
>> of a module instead, that is, the "real" exports.
> 
> Thanks again for the patch, I've pushed it and closed #1121.  I've also
> updated NEWS to mention the bugfix and new feature.  I liked the fact
> that you added some comments, they helped me to understand what the code
> was doing more easily!
> 
> I didn't fully grok the bugfix, so I wrote a simple test program to
> verify that I understood what it was doing, but while this doesn't
> fail as hard as before the patch, it's still not working.  Could you
> take a look at the attached file?
> 
> I think this may actually indicate two bugs: the functor complains
> about unbound identifiers, but if I compile the following simple
> program:
> 
> (use csi)
> (toplevel-command 'blabla (lambda _ (print "blabla")))
> 
> I also get an error that "csi" can't be loaded.

The functor needs to import "chicken" to detect the #!optional (i.e.
extended lambda-lists - yes, the warning is misleading and doesn't
give the "#!", don't ask me why, I don't know).

It also needs to import "csi-like".

And finally, use "import" for the "csi" module:

:
(import csi)
(module foo-with-csi = (foo csi))
:


felix