Re: canonical name ending "-p"

[Evans Winner <ego111@gmail.com>]

,------ ken wrote ------
|    Lots of things in elisp end in "-p"... is there some
|    particular meaning in this?

On a related note (since Pascal already explained it) I have
wondered why the rather odd use of the term "predicate" was
chosen.

When I hear the term "predicate" I usually think of its
meaning in grammar and logic.  But there is also the use in
which one says that if one thing (A) depends on another
thing (B) that A is "predicated on B."  I suspect it is
because one might verbally reason that in:

   (if (atom t) t nil)

the answer to whether Lisp will return t or nil is
predicated on the results of (atom t), therefore by
extension we call the function itself a predicate.  It's a
little confusing because it is not one of the common uses of
the noun "predicate."  I would be interested to hear from
someone who knows if this is indeed the sense on which the
term was chosen.