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Groups > alt.folklore.computers > #164789

Re: BLISS

From Bob Eager <news0006@eager.cx>
Newsgroups alt.folklore.computers
Subject Re: BLISS
Date 2016-06-08 11:33 +0000
Message-ID <drqe3gFc6elU30@mid.individual.net> (permalink)
References <nj1fdd$li5$1@dont-email.me> <575735ef.21428362@nntp2.rawbw.com> <310680259.487077503.499123.peter_flass-yahoo.com@news.eternal-september.org>

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On Wed, 08 Jun 2016 07:26:08 -0400, Peter Flass wrote:

> Questor <usenet@only.tnx> wrote:
>> On Sun, 5 Jun 2016 16:10:31 +0100, "gareth G4SDW GQRP #3339"
>> <no.spam@thank.you.invalid> wrote:
>>> Inspired by the PL/I thread, I've had a look at BLISS for the first
>>> time.
>>> 
>>> Interesting the dot notation to cause a variable name dereference in
>>> sharp contrast to the C technique of using "&" to force a reference!
>> 
>> Except that C doesn't require "&" in an assignment statement, so there
>> still is an l-value/r-value dichotomy.
>> 
>> 
>>> I wonder how many bugs came about in BLISS programs because of the
>>> unnatural need to use dot compared to other languages?
>> 
>> One gets used to it very quickly when working with the code all day.
>> It did result in an interesting bug once.
>> 
>> A program that had been working for years started failing one day with
>> a page fault, and I quickly determined that what had changed was the KL
>> had received a microcode update.  I scrambled to find another machine
>> that hadn't yet been upgraded to determine how it had worked
>> previously.  I discovered there was a missing dot operator, and
>> consequently the pointer to a field specified a non-existant page. 
>> Under the old microcode, the write operation triggered the creation of
>> a page, the page map was duly updated, and the value written to an
>> otherwise empty page.  When the program subsequently went to read said
>> value with the same pointer, there it was -- right where it had been
>> written.
>> I don't remember the reason for the microcode change, but now the same
>> write request caused a page fault.  Anyway, I added the missing dot to
>> the pointer construction and all was right with the world again.
>> 
>> The big problem with the dot operator is that a period does not have a
>> lot of "visual redundancy," if you will.  It is at the mercy of fading
>> ink ribbons, coffee stains, blurry CRT screens, etc.  I don't know what
>> the better choice would have been, but I wish someone had found it.
>> 
>> Otherwise, I like the clear line that BLISS draws between l-values and
>> r-values.
>> 
>> 
>> 
> Where did the terms l-value and r-value originate?  The first place I
> saw them was C, maybe K&R, were they original there or did they come
> earlier?

They are there in the definition of BCPL, and I believe in the definition 
of CPL.

(I have just unearthed the CPL manual from the other side of the room, 
and I can't find lvalues and rvalues mentioned).

But certainly in BCPL, so I would guess mid 1960s. Clearly before C, 
since BCPL begat B, which begat C.



-- 
Using UNIX since v6 (1975)...

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Thread

BLISS "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-06-05 16:10 +0100
  Re: BLISS Bob Eager <news0006@eager.cx> - 2016-06-05 15:25 +0000
  Re: BLISS Peter Flass <peter_flass@yahoo.com> - 2016-06-05 12:25 -0400
    Re: BLISS "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-06-05 18:41 +0100
  Re: BLISS Al Kossow <aek@bitsavers.org> - 2016-06-05 12:20 -0700
    Re: BLISS "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-06-05 23:08 +0100
      Re: BLISS Morten Reistad <first@last.name.invalid> - 2016-06-06 07:38 +0200
        Re: BLISS "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-06-06 09:33 +0100
          Re: BLISS Morten Reistad <first@last.name.invalid> - 2016-06-06 13:05 +0200
            Re: BLISS jmfbahciv <See.above@aol.com> - 2016-06-06 13:35 +0000
            Re: BLISS "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-06-06 14:54 +0100
              Re: BLISS Al Kossow <aek@bitsavers.org> - 2016-06-06 08:03 -0700
                Re: BLISS "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-06-06 16:07 +0100
                Re: BLISS Al Kossow <aek@bitsavers.org> - 2016-06-06 08:11 -0700
                Re: BLISS jmfbahciv <See.above@aol.com> - 2016-06-07 12:11 +0000
                Re: BLISS Quadibloc <jsavard@ecn.ab.ca> - 2016-06-08 02:31 -0700
                Re: BLISS Bob Eager <news0006@eager.cx> - 2016-06-08 10:26 +0000
                Re: BLISS "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-06-08 12:01 +0100
                Re: BLISS scott@slp53.sl.home (Scott Lurndal) - 2016-06-06 16:48 +0000
                Re: BLISS Peter Flass <peter_flass@yahoo.com> - 2016-06-07 16:14 -0400
      Re: BLISS JimP <solosam90@gmail.com> - 2016-06-06 14:16 -0500
  Re: BLISS jmfbahciv <See.above@aol.com> - 2016-06-06 13:35 +0000
  Re: BLISS usenet@only.tnx (Questor) - 2016-06-07 21:04 +0000
    Re: BLISS Bob Eager <news0006@eager.cx> - 2016-06-07 22:30 +0000
      Re: BLISS "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-06-08 10:23 +0100
        Re: BLISS Bob Eager <news0006@eager.cx> - 2016-06-08 10:24 +0000
      Re: BLISS jmfbahciv <See.above@aol.com> - 2016-06-08 12:09 +0000
        Re: BLISS Bob Eager <news0006@eager.cx> - 2016-06-08 12:27 +0000
        Re: BLISS Quadibloc <jsavard@ecn.ab.ca> - 2016-06-08 07:48 -0700
          Re: BLISS Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2016-06-08 15:21 +0000
          Re: BLISS Peter Flass <peter_flass@yahoo.com> - 2016-06-08 11:50 -0400
            Re: BLISS Quadibloc <jsavard@ecn.ab.ca> - 2016-06-08 09:32 -0700
            Re: BLISS - broken bar Dan Espen <despen@verizon.net> - 2016-06-08 15:35 -0400
              Re: BLISS - broken bar Peter Flass <peter_flass@yahoo.com> - 2016-06-09 10:52 -0400
              Re: BLISS - broken bar Joe Makowiec <makowiec@invalid.invalid> - 2016-06-09 20:11 +0000
                Re: BLISS - broken bar Peter Flass <peter_flass@yahoo.com> - 2016-06-10 06:45 -0400
          Re: BLISS jmfbahciv <See.above@aol.com> - 2016-06-09 12:25 +0000
            Re: BLISS Dave Garland <dave.garland@wizinfo.com> - 2016-06-09 10:23 -0500
              Re: BLISS Quadibloc <jsavard@ecn.ab.ca> - 2016-06-09 08:49 -0700
            Re: BLISS "J. Clarke" <j.clarke.873638@gmail.com> - 2016-06-09 20:07 -0400
              Re: BLISS Quadibloc <jsavard@ecn.ab.ca> - 2016-06-09 19:11 -0700
                Re: BLISS Quadibloc <jsavard@ecn.ab.ca> - 2016-06-09 19:16 -0700
      Re: BLISS "Charles Richmond" <numerist@aquaporin4.com> - 2016-06-11 10:09 -0500
        Re: BLISS Bob Eager <news0006@eager.cx> - 2016-06-11 16:05 +0000
          Re: BLISS Ahem A Rivet's Shot <steveo@eircom.net> - 2016-06-11 19:27 +0100
            Re: BLISS Bob Eager <news0006@eager.cx> - 2016-06-11 18:46 +0000
          Re: BLISS "Charles Richmond" <numerist@aquaporin4.com> - 2016-06-12 09:45 -0500
    Re: BLISS "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-06-08 10:21 +0100
    Re: BLISS Peter Flass <peter_flass@yahoo.com> - 2016-06-08 07:26 -0400
      Re: BLISS Bob Eager <news0006@eager.cx> - 2016-06-08 11:33 +0000
        Re: BLISS "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-06-08 13:30 +0100
          Re: BLISS Bob Eager <news0006@eager.cx> - 2016-06-08 14:07 +0000
            Re: BLISS "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-06-08 15:39 +0100
              Re: BLISS Quadibloc <jsavard@ecn.ab.ca> - 2016-06-08 07:56 -0700
                Re: BLISS Peter Flass <peter_flass@yahoo.com> - 2016-06-08 11:50 -0400
              Re: BLISS Bob Eager <news0006@eager.cx> - 2016-06-08 15:27 +0000
              Re: BLISS Peter Flass <peter_flass@yahoo.com> - 2016-06-08 11:50 -0400
                Re: BLISS "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-06-08 17:13 +0100
                Re: BLISS mausg@mail.com - 2016-06-09 09:37 +0000
                Re: BLISS Peter Flass <peter_flass@yahoo.com> - 2016-06-09 10:52 -0400
              Re: BLISS Alan Bowler <atbowler@thinkage.ca> - 2016-06-28 18:53 -0400
                Re: BLISS Peter Flass <peter_flass@yahoo.com> - 2016-06-28 19:47 -0400
                Re: BLISS "J. Clarke" <j.clarke.873638@gmail.com> - 2016-06-28 20:00 -0400
                Re: BLISS "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-06-29 09:19 +0100
                Re: BLISS "J. Clarke" <j.clarke.873638@gmail.com> - 2016-06-29 04:43 -0400
                Re: BLISS "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-06-29 09:17 +0100
                Re: BLISS Quadibloc <jsavard@ecn.ab.ca> - 2016-07-12 17:07 -0700
                Re: BLISS mausg@mail.com - 2016-07-13 14:22 +0000
                Re: BLISS mausg@mail.com - 2016-07-13 14:41 +0000
                Re: BLISS Ahem A Rivet's Shot <steveo@eircom.net> - 2016-07-13 16:50 +0100
                Re: BLISS mausg@mail.com - 2016-07-13 19:24 +0000
                Re: BLISS Alfred Falk <falk@arc.ab.ca> - 2016-07-13 23:13 +0000
                Re: BLISS Bob Martin <bob.martin@excite.com> - 2016-07-14 06:06 +0100
                Re: BLISS Ahem A Rivet's Shot <steveo@eircom.net> - 2016-07-14 09:12 +0100
            Re: BLISS Ahem A Rivet's Shot <steveo@eircom.net> - 2016-06-08 15:42 +0100
              Re: BLISS Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2016-06-08 15:21 +0000
                Re: BLISS "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-06-08 16:44 +0100
                Re: BLISS "Charles Richmond" <numerist@aquaporin4.com> - 2016-06-11 10:19 -0500
                Re: BLISS Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2016-06-13 16:20 +0000
              Re: BLISS Bob Eager <news0006@eager.cx> - 2016-06-08 15:28 +0000
        Re: BLISS Ahem A Rivet's Shot <steveo@eircom.net> - 2016-06-08 14:40 +0100
          Re: BLISS Bob Eager <news0006@eager.cx> - 2016-06-08 14:08 +0000
          Re: BLISS Alan Bowler <atbowler@thinkage.ca> - 2016-07-12 19:15 -0400
            Re: BLISS David Wade <dave.g4ugm@gmail.com> - 2016-07-13 17:39 +0100
      Re: BLISS "gareth G4SDW GQRP #3339" <no.spam@thank.you.invalid> - 2016-06-08 13:29 +0100

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