vi editor -- how do you :unmap or :unabbreviate all settings?

[Timothy D. Gill]

I find that I exceed the limit in the vi editor for defining mapped keys and
abbreviations: I have about 40 total of both defined for my normal day-to-day
use.  However, I have an additional 20 defined for use with Bibliography
creation and C program creation.  I have worked out a way using csh aliases
for invoking vi for bibliography or C files so that I get a different .exrc
file to be used, but I would rather use the :unmap, :unabbreviate and :source
commands in vi to change my maps and abbreviations.  This would allow me to
stay in a single vi session all day, and only change my maps and abbreviations
when I need to.

My question is: is there a quick way to unmap and unabbreviate ALL of my
current mappings and abbreviations, such that I could so a sequence, say, like this:

   :unmap *
   :unab  *
   :source $HOME/.vi-maps-for-C

I have tried using   *   or   all   as an argument to both the :unmap and the
:unab commands, but this does not work.  And I cannot find another command to
do it.

We have vi Version 3.7, 6/10/83, under Ultrix 1.0 (BSD 4.1).