Re: enhancement requests

[Wolfgang J Moeller <wjm@heenes.com>]

On Tue, 29 Mar 2011, Andy Wingo wrote:

>[...]
> >  (a) undo MACRO definitions - you can't re-DEFINE a name after DEFINE-SYNTAX;
>
> You can certainly re-define a name after define-syntax.  This used to
> not be the case, at least with psyntax, but this changed at some point
> in upstream psyntax, and I merged in similar functionality in our copy
> sometime last year or the year before.

Sorry. I could have sworn ... but I must have confused it with GUILE 1.8.

> >  (b) recover built-in functions once you have re-defined them;
>
> Hummmm.  However, functions which have been defined in your module in
> terms of your local functions might keep a hold on your local functions.
> Whether this happens depends on whether the code in question has been
> run or not, and whether the code was introduced from a macro or not.
> For the mechanism, see "Compiled Procedures are VM Programs" in the
> manual.
>
> Basically I'm hesitant to include such functionality in Guile itself,
> because it gets harder for me (as maintainer, bug-hunter, etc) to reason
> about users' code after you ,undefine.

OK, that's a rather exotic point. I came across it since my "prelude"
traditionally re-defines the "while" macro [to work as it should have
in GUILE 1.6, i.e. allowing for an optional result argument to "break"].

> >  (c) test code that uses UNDEFINED? .
>
> How is this different from (not (defined? 'sym)) ?  And what kind of
> code would you use this for?

Sorry, in fact I did mean the function "defined?".
Used in my prelude, because GUILE - my first Scheme - used to provide it.

===

On Thu 17 Mar 2011 12:50, Andy Wingo <wingo@pobox.com> writes:

>>> (3) documentation: Please do document that ~/.guile is (often) invoked
>>>     automatically (old omission), and what options (including
>>>     _undocumented_ "-q") inhibit this.
>>
>> Will do.
>
> Done.

Thanks a lot!

Best regards,

Wolfgang J. Moeller, Tel. +49 551 47361, wjm<AT>heenes.com
37085 Goettingen, Germany | Disclaimer: No claim intended!
http://www.wjmoeller.de/ -+-------- http://www.heenes.com/