differencial form package



Hello Gosei,

Thanks very much for sending the differential forms package.
This is terrific! This will be a great addition to Maxima's capability.

I have committed the files to maxima/share/diff_form/,
in the process renaming cartan_init.bat to diff_form.mac
and renaming new_cartan_test4.bat to new_cartan_test4.mac,
and removing load(...) from new_cartan_test4.mac.

I was working through surface_example.txt and I ran into the following problem.
d(translist);
 => No such list element: [0]

which appears to come from the definition of @ in cartan_new.lisp.
dispfun("@") shows "for i from dim step -1 thru 0 do ..." and that
seems to cause the problem because basis[i] is in the loop.
After changing "thru 0" to "thru 1", the rest of the example seems
to work as shown in surface_example.txt.
Should we change cartan_new.lisp (line 56) accordingly ??

Thanks again for your contribution to Maxima. I appreciate it a lot.

Robert Dodier