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Re: illegal uses of define in guile
From: |
Bruce Korb |
Subject: |
Re: illegal uses of define in guile |
Date: |
Mon, 14 Oct 2002 10:49:50 -0700 |
Dirk Herrmann wrote:
>
> Currently, guile allows the following:
> (if (not (defined? '%load-verbosely))
> (define %load-verbosely #f))
I do that.
> This is in contrast to R5RS (maybe even already in contrast to R4RS,
> but I haven't checked that). Allowing such placements of define will make
> it impossible to determine statically whether after evaluation of the
> form the corresponding identifier will be bound or not. That is, we
> should disallow this behaviour.
Just because static analysis is hard/difficult/impossible
does not mean you have to disallow the construct. It may
mean you have to disable "memoization" or "optimization"
of it -- that's okay. But invalidating peoples work just
because you have an optimization problem, ... well it is
as bad as saying you cannot alias an "intptr_t" with a
pointer in C.
> Second, we should decide about how to deal with such forms. Since guile
> has allowed this before, there may exist code that makes use of this
> feature. It will, however, be difficult to support this feature as
> 'deprecated' when separating memoization and execution.
:-(
- illegal uses of define in guile, Dirk Herrmann, 2002/10/14
- Re: illegal uses of define in guile,
Bruce Korb <=
- Re: illegal uses of define in guile, Neil Jerram, 2002/10/14
- Re: illegal uses of define in guile, Bruce Korb, 2002/10/14
- Re: illegal uses of define in guile, Dirk Herrmann, 2002/10/15
- Re: illegal uses of define in guile, tomas, 2002/10/15
- Re: illegal uses of define in guile, rm, 2002/10/15
- Re: illegal uses of define in guile, Bruce Korb, 2002/10/15
Re: illegal uses of define in guile, rm, 2002/10/15
Re: illegal uses of define in guile, Marius Vollmer, 2002/10/18