From: Marcin Borkowski <mbork@mbork.pl>
To: help-gnu-emacs@gnu.org
Subject: Re: no empty (zero) string predicate in Elisp
Date: Sun, 26 Apr 2015 22:11:50 +0200 [thread overview]
Message-ID: <87lhhebqex.fsf@mbork.pl> (raw)
In-Reply-To: <87tww2zp3f.fsf@debian.uxu>
On 2015-04-26, at 21:06, Emanuel Berg <embe8573@student.uu.se> wrote:
> Marcin Borkowski <mbork@mbork.pl> writes:
>
>>> "Predicate" is a word from the grammars of human
>>> languages, but I don't know its exact meaning,
>>> neither there or in programming languages (until
>>> now as for programming).
>>
>> AFAIK, "predicate" is a word from /logic/, and it
>> means (more or less) a function which consumes one
>> or more arguments of any type and gives back
>> a truth-value.
>
> Doesn't all functions in logic do that?
First of all: IANAL (here L = logician;-)). But...
For starters, in propositional calculus (AFAIK, also in first-order
logic) there are no "functions" per se, since there are no /sets/.
Furthermore, in the logic systems usually used by us mathematicians
there are no /types/. AFAIK, the analogue of "type mismatch" in these
systems is just a plain old "syntax error".
What you probably refer to is the fact that in these simple logic
systems both predicates and logical connectives "generate"
truth-values. However, there are other possibilities; analogues of
"functions" in these systems are called "terms".
Best,
--
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Faculty of Mathematics and Computer Science
Adam Mickiewicz University
next prev parent reply other threads:[~2015-04-26 20:11 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-25 3:44 no empty (zero) string predicate in Elisp Emanuel Berg
2015-04-25 9:26 ` Nicolas Petton
2015-05-16 9:23 ` Nicolas Petton
2015-05-16 13:22 ` Bozhidar Batsov
2015-05-16 13:28 ` Bozhidar Batsov
2015-05-16 13:36 ` Bozhidar Batsov
2015-05-16 13:46 ` Eli Zaretskii
2015-05-16 16:17 ` Bozhidar Batsov
2015-05-16 13:43 ` Stefan Monnier
2015-05-16 15:27 ` Drew Adams
[not found] ` <mailman.1583.1429954907.904.help-gnu-emacs@gnu.org>
2015-04-25 11:22 ` Emanuel Berg
2015-04-25 13:30 ` Stefan Monnier
[not found] ` <mailman.1591.1429968677.904.help-gnu-emacs@gnu.org>
2015-04-25 14:48 ` Pascal J. Bourguignon
2015-04-26 2:52 ` Stefan Monnier
2015-04-27 10:28 ` zerop: compiler macro vs defsubst (was: no empty (zero) string predicate in Elisp) Nicolas Richard
2015-04-27 12:19 ` zerop: compiler macro vs defsubst Stefan Monnier
[not found] ` <mailman.1626.1430016741.904.help-gnu-emacs@gnu.org>
2015-04-26 4:06 ` no empty (zero) string predicate in Elisp Pascal J. Bourguignon
2015-04-26 21:25 ` Stefan Monnier
2015-04-26 4:26 ` Rusi
2015-04-26 12:36 ` Emanuel Berg
2015-04-26 15:03 ` Pascal J. Bourguignon
2015-04-26 18:34 ` Emanuel Berg
2015-04-26 18:59 ` Marcin Borkowski
[not found] ` <mailman.1658.1430074770.904.help-gnu-emacs@gnu.org>
2015-04-26 19:06 ` Emanuel Berg
2015-04-26 20:11 ` Marcin Borkowski [this message]
[not found] ` <mailman.1662.1430079142.904.help-gnu-emacs@gnu.org>
2015-04-27 1:00 ` Emanuel Berg
2015-04-26 17:28 ` Rusi
2015-04-26 18:39 ` Emanuel Berg
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