From: Fernando Mato Mira
Subject: Re: What does #+<anything-here> mean?
Date:
Message-ID: <379C91A0.A096D411@iname.com>
Barry Margolin wrote:
> In article <············@nnrp1.deja.com>, <······@my-deja.com> wrote:
> >In article <·················@iname.com>,
> > Fernando Mato Mira <········@iname.com> wrote:
> >> Rob Warnock wrote:
> >>
> >> > By the way, very few Schemes implement #+/#-
> >>
> >> And it's a very bad situation.
> >
> >I'd like to know why this capability is considered to be this important.
> >(Not meant as a flame. My only only Common Lisp programming has
> >been out of books.)
>
> It's intended to allow you to write programs or data files that will work
> in a variety of Lisp dialects. E.g. you can write something like:
It's not useful only for that. Mainly it's used for differences in
_implementations_.
I have some files that won't work across different Schemes, unless the capability
is there. I had to add it to Gambit and MzScheme to be able to switch between them
(just because there was no debugger in MzScheme).
I never sent the Gambit changes. And I doubt MzScheme has integrated them (mflatt
rightly
refused to the global *FEATURES*, and suggested using an MzScheme `parameter'
instead but I never got to it, as the hack worked for me (and I haven't been using
MzScheme for over a year)).
[X3J13 NOTE #2: Add accessors for *FEATURES*]