DIGITP again, and again and again

[Glenn S. Burke <GSB at MIT-ML>]

Just to lend some balance to the pros, cons, and utilities of various
definitions, i feel i should point out that the usage i have consistently
wanted was whether the character in question was one of the characters
0-9.  (For what it's worth, that fits the first definition given in my
Webster's.)  On the other hand, i have not been writing a general
token reader, but i also doubt that most users will spend their time
doing that.  Looks to me like an optional second arg of the base, default
10., is the best choice.  If nothing else, one should have powerful
primitives for doing class tests on the character set, (alphabeticp,
alphanumericp, digitp, etc;  forgive me for not reviewing CHPROP), and
these primitives should be independent of the parameters used by Lisp
itself (ibase, readtable) so that they can be generally used in contexts
where those parameters have no meaning.