Kevin Wortman scripsit:

> "Note that an SRE is a first-class object consisting of nested lists
> of strings, chars, char-sets, symbols and numbers. Where the syntax is
> described as (foo bar), this can be constructed equivalently as '(foo
> bar) or (list 'foo 'bar), etc."

Right.  So it's not a *disjoint* data type, as compiled re's and
regex-match objects are.  But that doesn't mean it doesn't deserve a
predicate, even if you have to be sure to check that predicate before
any of the built-in ones.

--
Do what you will,                       John Cowan
   this Life's a Fiction                xxxxxx@ccil.org
And is made up of                       http://www.ccil.org/~cowan
   Contradiction.  --William Blake