[seqfan] Re: J-language.

Simon Plouffe simon.plouffe at gmail.com
Fri Jul 2 08:55:25 CEST 2010


As far as the standard definition is there, I agree with that entry.

best regards,

simon plouffe



2010/7/2 Antti Karttunen <antti.karttunen at gmail.com>

> Douglas McNeil, Simoun Plouffe and Joerg Arndt wrote about the J language
> (see below).
>
> No, it's not a joke, but a matrix language based on APL, where the special
> function/operator signs of APL has been replaced with the familiar and more
> easily remembered ASCII characters. ;-)
> And I actually downloaded it just two days ago, for computing a few
> specific
> sequences to OEIS.
>
> Cheers,
>
> Antti Karttunen
>
> On Fri, Jul 2, 2010 at 1:18 AM, <seqfan-request at list.seqfan.eu> wrote:
>
> > Send Seqfan mailing list submissions to
> >        seqfan at list.seqfan.eu
> >
> >
> > ------------------------------
> >
> > Message: 10
> > Date: Thu, 1 Jul 2010 20:20:25 +0800
> > From: Douglas McNeil <mcneil at hku.hk>
> > Subject: [seqfan]  most obscure OEIS code ever?
> > To: Sequence Fanatics Discussion list <seqfan at list.seqfan.eu>
> > Message-ID:
> >        <AANLkTim53f6Fhm2FDQtYD_9avxhmrXXmaOcpuSBmhRD3 at mail.gmail.com>
> > Content-Type: text/plain; charset=ISO-8859-1
> >
> > %o A178683 (J programming language, see http://www.jsoftware.com)
> > %o A178683 . aXXXX =: (5 #. ] {::~ [: (i. >./) */&>)@:part"0
> > %o A178683 . part =: 3 : 'final (, new)^:y <<i.1 0' NB. Here & below due
> to
> > Hui
> > %o A178683 . final=: ; @: (<@-.&0"1&.>) @ > @ {:
> > %o A178683 . new =: (-i.)@# <@:(cat&.>) ]
> > %o A178683 . cat =: [ ;@:(,.&.>) -@(<.#) {. ]
> >
> > There are a handful of other sequences with J codes, but this is
> > probably the most impressive.  Surprisingly, J appears not to be a
> > parody esolang, which was my first guess-- or if it is, the authors
> > have admirably moved all-in on the joke and have kept their tongues in
> > their cheeks for almost twenty years.  One's tempted to suspect a
> > drunken bet gone horribly, horribly wrong..
> >
> >
> > Doug
> >
> > --
> > Department of Earth Sciences
> > University of Hong Kong
> >
> >
> >
> > ------------------------------
> >
> >
> >
> > Message: 13
> > Date: Thu, 1 Jul 2010 15:09:56 +0200
> > From: Simon Plouffe <simon.plouffe at gmail.com>
> > Subject: [seqfan] Re: most obscure OEIS code ever?
> > To: Sequence Fanatics Discussion list <seqfan at list.seqfan.eu>
> > Message-ID:
> >        <AANLkTindomzIu7WOnKhtYH4eJqe4GN37Ar0v1V4ozTCL at mail.gmail.com>
> > Content-Type: text/plain; charset=ISO-8859-1
> >
> > sorry, but this resembles a kind of joke in smiley language
> > more thana real program,
> >
> > (my own opinion), I don't see the point of
> > having sequences coded in that kind of
> > cryptic language.
> >
> > for example for n!, one can give an example
> > of a very short C, or whatever language that
> > would produce the sequence, that's ok. but
> > to have a sequence that has only that is not
> > a good idea. ... Some perl programs can be
> > made impossible to decode, this is a useless
> > exercice.
> > we need the name, the ref. something to
> > sitck to what is known.
> > (end of personal comment).
> >
> > best regards,
> >
> > Simon Plouffe
> >
> >
> > ------------------------------
> >
> > Message: 14
> > Date: Thu, 1 Jul 2010 15:46:48 +0200
> > From: Joerg Arndt <arndt at jjj.de>
> > Subject: [seqfan] Re: most obscure OEIS code ever?
> > To: Sequence Fanatics Discussion list <seqfan at list.seqfan.eu>
> > Message-ID: <20100701134648.GA12036 at jjj.de>
> > Content-Type: text/plain; charset=us-ascii
> >
> > * Douglas McNeil <mcneil at hku.hk> [Jul 01. 2010 14:55]:
> > > %o A178683 (J programming language, see http://www.jsoftware.com)
> > > %o A178683 . aXXXX =: (5 #. ] {::~ [: (i. >./) */&>)@:part"0
> > > %o A178683 . part =: 3 : 'final (, new)^:y <<i.1 0' NB. Here & below
> due
> > to Hui
> > > %o A178683 . final=: ; @: (<@-.&0"1&.>) @ > @ {:
> > > %o A178683 . new =: (-i.)@# <@:(cat&.>) ]
> > > %o A178683 . cat =: [ ;@:(,.&.>) -@(<.#) {. ]
> > >
> >
> > sendmail.conf on steroids, I am thoroughly impressed.
> >
> >
> > > There are a handful of other sequences with J codes, but this is
> > > probably the most impressive.  Surprisingly, J appears not to be a
> > > parody esolang, which was my first guess-- or if it is, the authors
> > > have admirably moved all-in on the joke and have kept their tongues in
> > > their cheeks for almost twenty years.  One's tempted to suspect a
> > > drunken bet gone horribly, horribly wrong..
> > >
> >
> > Well, it's a concise language indeed,
> > the following (supposedly) computes A005249:
> >
> >  H=: % @: >: @: (+/~) @: i.
> >  det=: -/ .*
> >
> > Not sure about readability  ;-)
> >
> > http://en.wikipedia.org/wiki/J_(programming_language)<http://en.wikipedia.org/wiki/J_%28programming_language%29>
> <http://en.wikipedia.org/wiki/J_%28programming_language%29>
> > cf. also http://en.wikipedia.org/wiki/Tacit_programming
> > " ... or more pithily as pointless programming."
> >
> > Maybe this really is an in-joke of epic proportions.
> >
> >
> > >  [...]
> >
> >
> >
> >
>
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