[Maxima-discuss] #+maxima (progn (in-package :maxima) (defun ...))

[Eduardo O. <edu...@gm...>]

Hi all,

in another thread I was discussing LispTree, that at this moment has
three files - two ".lisp" files and one ".mac" file. Link:

  http://anggtwu.net/lisptree.html

The functions in the file "lisptree.lisp" can be tested in SBCL
without loading Maxima, but the file "lisptree-middle.lisp" needs
Maxima.

I think that debugging the parts in Lisp can become easier if I merge
the two Lisp files into a single one, with a structure like this,

  (defpackage :lisptree (:use :common-lisp))
  (in-package :lisptree)
  ;; ...
  #+maxima
  (progn
    (in-package :maxima)
    ;; ...
    )

that only runs the second part if we are "inside Maxima"... but as far
as I know Maxima doesn't define a "feature", so the "#+maxima" would
have to replaced by something else that checks if

  (find-package :maxima)

is non-nil instead of checking if some "featurep" is non-nil...

Anyone knows a _good way_ to do that? I tried a bit with eval-when,
but I couldn't find a way to make the (in-package :maxima) be run in
compile-time as a top-level form - and because of that the `defun's in
the second part were running in "(in-package :lisptree)" instead of in
"(in-package :maxima)"...

  Thanks in advance!
    Eduardo...