HDTenEightyP/NetNews huggingface dataset:
From: bjornl@sics.se (Bj|rn Lisper)
Subject: Re: Is efficient backtracking feasible in functional languages?
Organization: Swedish Institute of Computer Science, Kista
	<1992Nov11.171742.18783@eua.ericsson.se>
Date: Thu, 12 Nov 1992 13:53:18 GMT

In article <1992Nov11.171742.18783@eua.ericsson.se> joe@erix.ericsson.se
(Joe Armstrong) writes:
>|> 
>|>    strangesucc n =	hd [x|x<-[0..];x>n];
>|> 
	   ....

>	Wonderfull  !!
>	This is the kind of stuff that gives FP a bad name :-)
>	Is their a transformation system which can prove that
>	strangesucc x == x + 1 ?

Was strangesucc a function from natural numbers or integers? In the latter
case "strangesucc x == x + 1" is false for x < 0. For natural numbers, quite
intricate knowledge about them is required to prove the equality: we must
know that n+1 is the least natural number such that n < n+1, for instance,
we must know that this number will, for all n, eventually show up in the
list defined by [x|x<-[0..]], and we must know that it is the first such
number that shows up. The latter two facts must be proved by induction, I
think, ultimately using the Peano axioms for natural numbers. The proof also
implies a proof of termination for the function. So, my answer is "not
without theorem proving capabilities".

A more general data flow analysis should, however, at least be able to find
that at most two elements in the list [x|x<-[0..]] need to be stored
simultaneously. This is since only one element is returned, every element in
the list can be computed using only the previous element, and the
termination test involves only the element to be returned and the argument
to the function. So a smart compiler should throw away the "internal" list
[x|x<-[0..]] completely and allocate two registers instead.  Apparently
compilers today aren't that smart.

Bjorn Lisper
From: rej@ukc.ac.uk (R.E.Jones)
Newsgroups: comp.lang.functional
Subject: Re: Is efficient backtracking feasible in functional languages?
Keywords: lazy evaluation, comprehensions, backtracking
Date: 12 Nov 92 14:47:22 GMT
Reply-To: rej@ukc.ac.uk (R.E.Jones)
Organization: Computing Lab, University of Kent at Canterbury, UK.

In article <1992Nov10.164456.18062@email.tuwien.ac.at> ulrich@mips.complang.tuwien.ac.at writes:
>
>strangesucc n =	hd [x|x<-[0..];x>n];
>
>This program should run in constant space and linear time [1].
>However, for the implementations I tried, it turns out that the program
>seems to run in linear space! For a small n as 10000 the program aborts
>due to memory problems. Also a rewriting of the program to encode list comprehensions explicitly did not yield the desired result.
>
>Is there ANY implementation of a lazy functional language to execute
>the program above in an efficient manner (i.e. in constant space)?
>-- 
>Ulrich Neumerkel, ulrich@dec4.wu-wien.ac.at ulrich@mips.complang.tuwien.ac.at
>TU-Wien, Vienna University of Technology, +431 58801 4477 fax +431 5057838
>Institut fuer Computersprachen E185/1 Argentinierstr.8/4, A-1040 Wien Austria


I've tried this on an implementation based on the G-machine. My machine
uses the blackholing technique to avoid space leaks that I describe in [1].
I translate list comprehensions to their equivalent using foldr, map and
concat; for example see [2].
I have no problem with this function: it runs in constant space (262 words
of heap space if you want to compare figures with those give in [1]).

[1] Richard E. Jones. `Tail recursion without space leaks', Journal of 
    Functional Programming 2(1), 73--79, January 1992.
    
[2] Richard Bird & Phil Wadler. `Introduction to Functional Programming', 
    Prentice Hall, 1988. Page 63.


Richard Jones

===============================================================================

Computing Laboratory				email: rej@ukc.ac.uk
University of Kent at Canterbury		Telephone: 0227 764000 ext.7550
Canterbury, CT2 7NF, U.K.			FAX: 0227 762811

===============================================================================
From: sfk@otter.hpl.hp.com (Steve Knight)
Date: Fri, 13 Nov 1992 11:40:21 GMT
Subject: Re: What's pop?
Organization: Hewlett-Packard Laboratories, Bristol, UK.
Newsgroups: comp.lang.pop

Sam writes:
> I thought it was Post Office Protocol.

There is indeed a "POP = Post Office Protocol" and the likely confusion was
discussed in the required debate.  At the end of this short debate no one
thought the risk of confusion between this protocol and the family of 
programming languages stemming from the original Edinburgh POP-2 language
was a matter for concern.

We chose POP because it covers variants such as POP-1, POP-2, POP-11, 
PopTalk, and AlphaPOP.  The intention is to include all programming dialects 
whose strongest influence can be traced back to that early Edinburgh 
development.  But how times change -- these days people have no respect for
the past (grumble, whinge) and we see modern day variants such as GLOW without
even the letter 'P' in it (mutter).

Apologies in advance to anyone who gets confused.

Steve

Newsgroups: comp.lang.pop
From: nikhil@crl.dec.com (R.S. Nikhil)
Subject: Re: help
Organization: DEC Cambridge Research Lab
Date: Thu, 12 Nov 1992 17:51:38 GMT

In article <1dtvigINNksp@agate.berkeley.edu>, bh@anarres.CS.Berkeley.EDU (Brian Harvey) writes:
> 
> POP is a programming language developed in the 1970s in England.

Ooooh!  That's Scotland, not England, I believe (Burstall, Collins, Popplestone et. al.
at Edinburgh)

Rishiyur S. Nikhil (nikhil@crl.dec.com)
Newsgroups: comp.lang.pop,alt.lang.basic
From: tlhouse@nyx.cs.du.edu (fiver)
Subject: Re: Ok, so pop *pop* may be a valid lang, but where's basic?
X-Disclaimer: Nyx is a public access Unix system run by the University
	of Denver for the Denver community.  The University has neither
	control over nor responsibility for the opinions of users.
Organization: Nyx, Public Access Unix at U. of Denver Math/CS dept.
Date: Fri, 13 Nov 92 00:34:14 GMT


Basic is where it belongs, in the alt., just like you said .. I don't know
from pop, but I *DO* know Basic is pretty much garbage when compared to
other GOOD languages .. (I'm talking just normal, everyday basic, none of
these silly basic compilers that look more like Pascal than Basic to me)
.. (come to think of it, they aren't much good either) .. is there any
*serious* development being done in Basic anymore?  Not really .. if so,
I'd like to know where .. anyway, if pop is like ProLog, then at least it
can be expected to be a serious language for its field .. Basic was good,
once, but its not anymore .. if this were the heyday of Basic, surely
there would be a comp.lang.basic .. as for the pop/prolog/lisp family of
languages, they are somewhat still in specialty use and haven't hit the
general development arena heavily, so its more likely we'll see some
"obscure" stuff here .. anyway, who cares?  Just listen and learn about
"pop" .. this has nothing to do with Basic anyway ..
From: bh@anarres.CS.Berkeley.EDU (Brian Harvey)
Newsgroups: comp.lang.pop
Subject: Re: help
Date: 13 Nov 1992 05:27:17 GMT
Organization: University of California, Berkeley
NNTP-Posting-Host: anarres.cs.berkeley.edu

nikhil@crl.dec.com (R.S. Nikhil) writes:
>Ooooh!  That's Scotland, not England, I believe (Burstall, Collins,
>Popplestone et. al.  at Edinburgh)

Oops!  Sorry about that -- the papers I have about POP are mostly from
Sussex, not Edinburgh, so I missed the connection.
Xref: sparky comp.lang.pop:19 alt.lang.basic:822
From: David.Beasley@cm.cf.ac.uk (David Beasley)
Newsgroups: comp.lang.pop,alt.lang.basic
Subject: Re: Ok, so pop *pop* may be a valid lang, but where's basic?
Date: 13 Nov 92 12:56:55 GMT
Organization: University of Wales College of Cardiff

Wayne Smith writes:
>Flame me all you want, but if some obscure UK language developed 20
>years ago can make it into a comp.lang group, why is basic still shit-upon 
>and relegated to the status of an alt group? (alt.lang.basic)?

Well, LISP and FORTRAN are _even_older_, and PROLOG is about the same age.
	
Pop has its own comp group for the simple reason that the people interested
in the language were organised enough to issue a RFD and a CFV.
If BASIC only has an alt group, perhaps its because the fans of BASIC
havent got their act together yet ;-)

Now, how would one of the people far better qualified than me like to explain
to all these uninitiateds what pop is, and why its so good ... ?


--

David Beasley                          (David.Beasley@cm.cf.ac.uk)    
Department of Computing Mathematics 
University of Wales College of Cardiff                          __o
PO Box 916                                                      \<,   
CARDIFF    CF2 4YN                         ___________________()/ ()___
From: kers@hplb.hpl.hp.com (Chris Dollin)
Newsgroups: comp.lang.pop
Subject: Re: Why is POP here? (was Re: help)
Date: 13 Nov 92 13:45:48 GMT
Organization: Hewlett-Packard Laboratories, Bristol, UK.


Several people wonder

   why this was a comp. group while BASIC is still an alt. group.

The simplest reason is (a) a mailing list existed for Pop, and was becoming
unmanagable due to bulk; this is an accepted reason for making a newsgroup; (b)
there is, by and large, only one dialect of Pop, all right, two, OK, several,
if you count the older versions; rather than very very many dialects of Basic;
(c) we had a CFD, a CFV, and enough Vs, to make a comp group. Lots of interest
in Pop comes from UK universities and companies and, strange as it might
appear, not all of these are going to get the alt groups.

[The main dialects of Pop are the Poplog version and AlphaPop. Steve will
probably Utter Words about the Pop9X Standard. If anyone gives me an opening to
discuss Pepper, rest assured I will take it.]

--

Regards,    | "Layered protocols give the software implementor a chance to
Kers.       | ruin his performance in each layer." - Don Gillies
From: kers@hplb.hpl.hp.com (Chris Dollin)
Newsgroups: comp.lang.pop
Subject: Re: Why is POP here? (was Re: help)
Date: 13 Nov 92 10:17:16 GMT
Organization: Hewlett-Packard Laboratories, Bristol, UK.

In article ... bh@anarres.CS.Berkeley.EDU (Brian Harvey) writes:

   There is also a more recent language
   called POPLOG that lets you mix POP notation with PROLOG.

Er, not quite.

Poplog is a *system*, not a language, which provides incremental compilers and
a screen editor for a variety of languages. The core language of the system is
Pop11 (descended for Pop2), the second (chronologically) language is Prolog;
Poplog also provides Common Lisp and Standard ML, and an interface to external
(typically C or Fortran) procedures. Poplog provides an interface to the Poplog
Virtual Machine which allows users to develop compilers for other languages,
although it's best at vaguely symbolic languages rather than the rinky-dinky
polish-the-bits kind.

I wonder who's going to write the FAQ or post the first definitive article?
Steve, Aaron, someone from Sussex, someone from ISL? It can't be me; I've got
two books to write. Loosely speaking.
--

Regards,    | "Layered protocols give the software implementor a chance to
Kers.       | ruin his performance in each layer." - Don Gillies
From: mal@hobbes.genrad.com (Mike A. Long)
Newsgroups: comp.lang.pop
Subject: Re: help
Date: 12 Nov 1992 09:46:01 -0500
Organization: GenRad, Inc.
Distribution: comp
NNTP-Posting-Host: hobbes.genrad.com



guaranteed to be a FAQ, what is pop?

please post, as this will be the initial FAQ, so someone might as well
start with that one.
-- 

#include "~/.sig/witty_sig.h"
Mike Long		mal@genrad.com
(508) 369-4400 x3023	Genrad, Inc.	Concord,Ma 01742 USA
Newsgroups: comp.lang.pop,alt.lang.basic
From: wlsmith@valve.heart.rri.uwo.ca (Wayne Smith)
Subject: Ok, so pop *pop* may be a valid lang, but where's basic?
Organization: (this space for rent)
Date: Thu, 12 Nov 1992 16:34:10 GMT

Flame me all you want, but if some obscure UK language developed 20
years ago can make it into a comp.lang group, why is basic still shit-upon 
and relegated to the status of an alt group? (alt.lang.basic)?

Newsgroups: comp.lang.pop,alt.lang.basic
From: etxmesa@eos.ericsson.se (Michael Salmon)
Subject: Re: Ok, so pop *pop* may be a valid lang, but where's basic?
Reply-To: etxmesa@eos.ericsson.se (Michael Salmon)
Organization: Ericsson Telecom AB
Date: Fri, 13 Nov 1992 08:45:58 GMT

In article <1992Nov12.163410.12678@julian.uwo.ca>, wlsmith@valve.heart.rri.uwo.ca (Wayne Smith) writes:
|> Flame me all you want, but if some obscure UK language developed 20
|> years ago can make it into a comp.lang group, why is basic still shit-upon 
|> and relegated to the status of an alt group? (alt.lang.basic)?
|> 

Actually shitting on basic is IMHO redundant :^)

-- 

Michael Salmon

#include	<standard.disclaimer>
#include	<witty.saying>
#include	<fancy.pseudo.graphics>

Ericsson Telecom AB
Stockholm
Xref: sparky comp.lang.pop:16 alt.lang.basic:821
From: uesu03@giac1.oscs.montana.edu (Lou Glassy)
Newsgroups: comp.lang.pop,alt.lang.basic
Subject: Re: Ok, so pop *pop* may be a valid lang, but where's basic?
Keywords: n
Date: 13 Nov 92 02:21:17 GMT
Article-I.D.: coe.1992Nov13.022117.20428
Organization: Montana State University, Bozeman  MT

It's easy to tip the baby out with the bathwater, especially
with Basic, which is not a 'cool' language anymore (like C, Ada,
etc.).   

Still, the development of Basic has not stood still.  Witness
TrueBasic, by the Dartmouth group that came out with the original
Basic almost 30 years ago.  TrueBasic could be chastened as
'looking like Pascal' [the cool language of the 1970s], but
one can write good, structured code with it, to solve simple
and small problems quickly.  

Lastly, Basic [in its various versions since the early 60s]
has made computers and computing a lot more accessible to a lot
more people than the other languages it ran beside.  

Is there a continuing niche for Basic?  I think so.  As long
as you want a simple little language for prototyping small
problems, the modern Basics can still hold their own, IMHO.

[None of this is intended to denigrate Pop, which from what
I've heard elsewhere, is an interesting tool for other things.
Personally, I could care less about whether Basic gets a comp.*
group or an alt.* group.  I'm glad it has a group I can access,
so I can see what people are doing with Basic these days.]

Lou.
-- 
Lou Glassy (uesu03@giac1.oscs.montana.edu)   Watch the field behind the plow
Earth Sciences Department                    Turn to straight, dark rows
Montana State University                     Put another season's promise
Bozeman, Montana 59715 USA                   In the ground...  --Stan Rogers
From: sfk@otter.hpl.hp.com (Steve Knight)
Date: Fri, 13 Nov 1992 11:22:56 GMT
Subject: Re: Ok, so pop *pop* may be a valid lang, but where's basic?
Organization: Hewlett-Packard Laboratories, Bristol, UK.
Newsgroups: comp.lang.pop

> Flame me all you want, but if some obscure UK language developed 20
> years ago can make it into a comp.lang group, why is basic still shit-upon 
> and relegated to the status of an alt group? (alt.lang.basic)?

Thanks for the invitation.  

I haven't followed the history of the attempt to to establish 
comp.lang.basic as a newsgroup.  However, Pop advocates followed the 
netiquette guidelines and got adequate support, largely drawn from the UK.  
I am astonished that the advocates of Basic didn't find the same level of
support.  I certainly would have voted for it.  I guess Basic is just
more obscure than Pop these days.

Better luck next time.

Steve
From: bh@anarres.CS.Berkeley.EDU (Brian Harvey)
Newsgroups: comp.lang.pop
Subject: Re: help
Date: 12 Nov 1992 16:08:48 GMT
Organization: University of California, Berkeley
Distribution: world
NNTP-Posting-Host: anarres.cs.berkeley.edu


POP is a programming language developed in the 1970s in England.
It combines an Algol-like syntax (statements separated with semicolons
inside block structures) with Lisp-like semantics (untyped variables,
lists as data aggregates, etc).  There is also a more recent language
called POPLOG that lets you mix POP notation with PROLOG.

The book _New Horizons in Educational Computing_ edited by Masoud Yazdani
(1984, Ellis Horwood Ltd/John Wiley & Sons) contains several articles
about POP.
From: jack@dcs.glasgow.ac.uk (Jack Campin)
Newsgroups: comp.lang.pop
Subject: PD Pop for the Mac?
Date: 13 Nov 92 14:23:04 GMT
Organization: Glasgow University Computing Science Dept.

Is there a public-domain Pop for the Mac?  (*NOT* under MPW, please God).

cheers - jack

-- 
--  Jack Campin    room G092, Computing Science Department, Glasgow University,
17 Lilybank Gardens, Glasgow G12 8RZ, Scotland   TEL: 041 339 8855 x6854 (work)
INTERNET: jack@dcs.glasgow.ac.uk or via nsfnet-relay.ac.uk    FAX: 041 330 4913
BANG!net: via mcsun and uknet     BITNET: via UKACRL    UUCP: jack@glasgow.uucp
Newsgroups: comp.lang.pop,alt.lang.basic
From: jmartens@magnus.acs.ohio-state.edu (Jeffrey D Martens)
Subject: Re: Ok, so pop *pop* may be a valid lang, but where's basic?
Organization: The Ohio State University
Date: Fri, 13 Nov 1992 01:21:08 GMT

In article <1992Nov12.163410.12678@julian.uwo.ca> wlsmith@valve.heart.rri.uwo.ca (Wayne Smith) writes:
>Flame me all you want, but if some obscure UK language developed 20
>years ago can make it into a comp.lang group, why is basic still shit-upon 
>and relegated to the status of an alt group? (alt.lang.basic)?

Sounds to me as though BASIC's getting a little more respect than
it deserves.  Perhaps there's something at least marginally
interesting about pop.  You can't honestly say that about BASIC,
now, can you?


From: sfk@otter.hpl.hp.com (Steve Knight)
Date: Fri, 13 Nov 1992 11:23:53 GMT
Subject: Re: What's pop?
Organization: Hewlett-Packard Laboratories, Bristol, UK.
Newsgroups: comp.lang.pop

> This must be a bogus group.  There was another bogus comp.lang group a month
> or 2 ago, and it didn't last too long.

And this must be a bogus posting?

Steve

Newsgroups: comp.lang.pop
From: plummer@cs.swarthmore.edu (David Barker-Plummer)
Subject: Re: Why is POP here? (was Re: help)
Organization: Swarthmore College, Swarthmore, PA
	<1dtvigINNksp@agate.berkeley.edu>
	<MJL.92Nov12133319@rigel.bos.locus.com>
Date: Fri, 13 Nov 1992 12:49:19 GMT

>>>>> On Thu, 12 Nov 1992 18:33:19 GMT, mjl@bos.locus.com (Mike Leibensperger) said:

ML> Sounds pretty obscure.  I have to agree with the guy who wondered
ML> why this was a comp. group while BASIC is still an alt. group.

The distinction between alt and comp groups has nothing to do with
prestige, obscurity or the subject under discussion, but to do with
interest.  If you want a basic group in comp, then you should issue a
call for discussion, followed by a call for votes, and if enough
people vote for the group it can be formed.  Just follow the
guidelines in news.groups.  If this has been tried, and there was no
interest then you can draw your own conclusions.

This group was constituted for the discussion of pop using these
rules.  If pop is "obscure" (I was educated at Edinburgh, so I don't
think so), then basic should easily get its own group.  Of course,
there will probably be discussion of whether comp.lang.basic is an
appropriate name for the group.

-- Dave
Newsgroups: comp.lang.pop
From: msanghvi@cs.ulowell.edu (Mehul Sanghvi)
Subject: help
Reply-To: msanghvi@cs.ulowell.edu
Organization: UMass-Lowell Comp. Sci. Dept.
Distribution: comp
Date: Thu, 12 Nov 1992 03:55:49 GMT



hello

GNUS POPped this newsgroup onto my list today and i was wondering what the
language pop is? i have never heard of it ( till now ) and would like to know
more about it out of curiosity. like does it have OO facilities in it?? is it
a high/medium/low level language ?? basic data types?? what's it used for??

is there an ftp'able compiler/interpreter available

hope someone can help out
--
===============================================================================
Mehul "raja lakhan" Sanghvi        |  UMass-Lowell Dept. of Computer Science
Inet: msanghvi@cs.ulowell.edu      |  SnailNet: 754 Aiken St. #11
UUCP: ...!harvard!ulowell!msanghvi |            Lowell, MA 01850-1804
BITNET: msanghvi%cs.ulowell.edu@{cunyvm.cuny, mitvma.mit, talcott.harvard}.edu

Abandon the search for Truth; settle for a good fantasy.
From: mjl@bos.locus.com (Mike Leibensperger)
Newsgroups: comp.lang.pop
Subject: Why is POP here? (was Re: help)
Date: 12 Nov 92 18:33:19 GMT
	<1dtqn9INN7kk@hobbes.genrad.com> <1dtvigINNksp@agate.berkeley.edu>
Organization: Locus Computing Corp., Boston Massachusetts USA.


In article <1dtvigINNksp@agate.berkeley.edu>
bh@anarres.CS.Berkeley.EDU (Brian Harvey) writes:

   POP is a programming language developed in the 1970s in England.
   It combines an Algol-like syntax (statements separated with semicolons
   inside block structures) with Lisp-like semantics (untyped variables,
   lists as data aggregates, etc).

Sounds pretty obscure.  I have to agree with the guy who wondered why
this was a comp. group while BASIC is still an alt. group.

BUT!  Maybe it *is* worth the bandwidth---I once knew a guy who wanted
to combine Algol and Lisp.  He told me...

	<drumroll please!>

...that that's where (defun ...) BEGINs!!!!

	Har har!
	mjl
--
Michael J. Leibensperger      "Rats and roaches live by competition under the
Locus Computing/Boston		 laws of supply and demand; it is the privilege
25 Mall Road; Burlington MA	     of human beings to live under the laws of
01803 (617)229-4980 mjl@locus.com       justice and mercy."  -- Wendell Berry
Member of the League for Programming Freedom --- write league@prep.ai.mit.edu
Newsgroups: comp.lang.pop
From: wlsmith@valve.heart.rri.uwo.ca (Wayne Smith)
Subject: What's pop?
Organization: (this space for rent)
Date: Thu, 12 Nov 1992 14:04:03 GMT

This must be a bogus group.  There was another bogus comp.lang group a month
or 2 ago, and it didn't last too long.

From: sfk@otter.hpl.hp.com (Steve Knight)
Date: Fri, 13 Nov 1992 11:31:03 GMT
Subject: Re: Re: help
Organization: Hewlett-Packard Laboratories, Bristol, UK.
Newsgroups: comp.lang.pop

Here's the original call for discussion posted by Ian Rogers of Sussex
University.  I hope this will answer some of the most obvious questions
about the intentions for this newsgroup.  There definitely needs to be
a FAQ list.  If anyone wants to start the ball-rolling on this, I'm
happy to act as coordinator.  The first FAQ is "What is POP?"; answers on
a postcard to this group ....

Steve

Ian's post follows:
> The group would serve for discussions on the programming language Pop11, and
> related environments and libraries.
> 
> Relevant topics, in this group, would cover all aspects of Pop11 programming
> (from novice questions to expert efficiency issues) and the current BSI
> standards effort (Pop9x).
> 
> Also relevant would be conversations about the Poplog programming environment
> and its libraries. Eg.
> 
>     OOP in Pop11 Flavours, or objectclass etc.
>     X windows hacking in Pop11
>     Mixed language programming (eg. between Lisp/Pop11/Prolog/ML/C etc.) that
>     is supported in Poplog but isn't relevant for discussion in other, pure
>     language, groups
>     Techniques for Artificial Intelligence programming (it is an AI language
>     after all :)
> 
> and so on.
> 
> These sorts of discussions have so far been supported by a mailing list. But
> the list is now far too unwieldy (>400 members). Universities are a constant
> hassle for the mailing list, with students leaving and joining all the time. A
> news group would serve these people much better.
> 
> Bandwidth is quite low.
> 
> The group would be gatewayed, at Univ. of Sussex, onto the mailing list for
> the industrial members with no internet access.
> 
> We seem to have done things backwards. We have a user group (Plug), an archive
> server, conferences and a standards effort, but no news group. I hope to
> rectify this :-)
Newsgroups: comp.lang.pop
From: choy@skorpio.usask.ca (I am a terminator.)
Subject: There it goes!
Organization: University of Saskatchewan, Saskatoon, Canada
Date: Thu, 12 Nov 1992 17:40:40 GMT

Pop goes the weasel!

Pop - sounds like a stack programmer's idea. Is there a push language
too?

Henry Choy