Re: canonical name ending "-p"

[rusi <rustompmody@gmail.com>]

On Mar 19, 1:36 am, Evans Winner <ego...@gmail.com> wrote:
> ,------ 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.

Maybe you are assuming the grammar use and not the logic use?
See disambiguating wikipedia page http://en.wikipedia.org/wiki/Predicate