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Re: canonical name ending "-p"
From: |
rusi |
Subject: |
Re: canonical name ending "-p" |
Date: |
Fri, 18 Mar 2011 21:32:37 -0700 (PDT) |
User-agent: |
G2/1.0 |
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