Re: [MIT-Scheme-users] associating environments with Scheme file buffers in Edwin

[Taylor Campbell]

   Date: Tue, 13 Sep 2005 15:50:05 -0400 (EDT)
   From: "Aaron S. Hawley" <address@hidden>

   [As a MIT Scheme /user/ and not a developer, I'm replying to the users
   list.]

   I think the nomenclature of "package" found in comments in MIT/GNU Scheme
   sources is showing package dependencies (like what is done in C with
   #includes), and really just duplicates the correct package information
   that exists in some .pkg file.

As I understand it (and an MIT Scheme developer or designer should
correct me if I misunderstand), the .pkg files are intended only for
two purposes: cross-referencing information and the automated
generation of loaders for systems.  While this is related to the
environment in which a file is intended to be loaded, the information
is not entirely analogous, it requires more effort than is necessary
to extract the desired information, and the desired information may
not even be present in the .pkg file, since the source file might not
be a regular package in a regular system at all (e.g., the .edwin
file).  It is also, as far as I have been able to discern from the
source, not very convenient to work with the package system during
dynamic development -- seems to CREF operate pretty statically.

   I'm not so sure about the necessity for creating the package-local
   variable facility you propose, but I think you've argued well for bringing
   Edwin's buffer-local variable system up to snuff with Emacs's.  Edwin
   supports something called "Edwin Variables" analogous to Emacs's "Local
   Variables".  Perhaps you haven't taken a look at that yet.  I would think
   that could set the `scheme-environment' variable as you wish.

Yes, I'm aware of this, but it's somewhat less convenient for the
purpose than I'd like, and it also departs from existing and well-
established Lisp tradition.  Also, it might be useful anyway to
provide the -*- line local variables facility for other libraries to
use.

   But you're right, their should be some consistency between Emacs and
   Edwin.  Unfortunately, I've read Edwin can barely mimic version 18(?) of
   GNU Emacs.

Well, there's a lot more to be done there and probably, unfortunately,
not quite enough effort to accomplish it.  I'm a bit more interested
in a useful Scheme environment, though, not just an exact Emacs clone.
(Also, I don't know of any Emacs library except a very recently made
one (namely scheme48.el) that respects a local 'package' variable.)