What do you think about using `!` instead of `set!` and `$` instead of
`ref`?  They are very short, preserve the !-convention, fit in nicely
with Gauche's `~`, and aren't much used in existing Schemes.  I ran them
through my 47 Schemes, and found only these:

Schemik excludes `$` from symbols, but doesn't seem to use it otherwise.

Llava uses `!` as a synonym for `not`.

Elk binds `!` to the value of the last expression evaluated at the REPL.

Inlab has a procedure `!` which invokes an editor on the last expression
typed at the REPL and evaluates it.

Owl Lisp uses `!` for the factorial function.

--
John Cowan          http://www.ccil.org/~cowan        xxxxxx@ccil.org
A rose by any other name may smell as sweet, but if you called it
an onion you'd get cooks very confused.          --RMS