8 Mar
2016
8 Mar
'16
7:01 p.m.
> https://www.bell-labs.com/usr/dmr/www/kbman.html
> https://www.bell-labs.com/usr/dmr/www/bintro.html
Yup, there certainly were different versions of B.
Yes, kbman covers only one of the two implementations that
cohabited the PDP-11. The other was the same language, with
software paging, so it could have a larger data space.
Various aspects of the language were borrowed from PL/I,
BCPL and Algol 68. ++ and -- were novel operators. The
reversal of Algol's assignment operators (e.g. -=
became =-) was eventually repealed in C.
doug
e
9 Mar
9 Mar
midnight
New subject: Documentation on B language?
Doug McIlroy scripsit:
Various aspects of the language were borrowed from
PL/I, BCPL and Algol
68. ++ and -- were novel operators. The reversal of Algol's assignment
operators (e.g. -= became =-) was eventually repealed in C.
Algol 68, like Algol 60 and Pascal, used := (pronounced "becomes") for
assignment, and the Algol 68 assignment operators were spelled :+=,
:-=, etc. (pronounced "plus and becomes", "minus and becomes", etc.)
Pre-increment operators were already known in Lisp 1.5 long before;
they are now spelled incf and decf in Common Lisp.
--
John Cowan http://www.ccil.org/~cowan cowan(a)ccil.org
If I have not seen as far as others, it is because giants were standing
on my shoulders. --Hal Abelson
1:10 a.m.
New subject: Documentation on B language?
How were they spelled in Lisp 1.5? The manual lists add1 and sub1, but says
nothing about them modifying the value of a variable.
Sent from my phone. Please excuse my brevity.
On Mar 8, 2016 10:20 AM, "John Cowan" <cowan(a)mercury.ccil.org> wrote:
Doug McIlroy scripsit:
Various aspects of the language were borrowed
from PL/I, BCPL and Algol
68. ++ and -- were novel operators. The reversal of Algol's assignment
operators (e.g. -= became =-) was eventually repealed in C.
Algol 68, like Algol 60 and Pascal, used := (pronounced "becomes") for
assignment, and the Algol 68 assignment operators were spelled :+=,
:-=, etc. (pronounced "plus and becomes", "minus and becomes", etc.)
Pre-increment operators were already known in Lisp 1.5 long before;
they are now spelled incf and decf in Common Lisp.
--
John Cowan http://www.ccil.org/~cowan cowan(a)ccil.org
If I have not seen as far as others, it is because giants were standing
on my shoulders. --Hal Abelson
1:43 a.m.
New subject: Documentation on B language?
Andru Luvisi scripsit:
How were they spelled in Lisp 1.5? The manual lists
add1 and sub1, but says
nothing about them modifying the value of a variable.
They may not have been in the very earliest 1.5, but rather in one of the
many 1.5 and 1.6 offshoots (which are documented mostly, if at all,
in unsearchable PDFs), probably spelled inc and dec. The add1 and sub1
functions (later spelled 1+ and 1-) have always been pure functional.
--
John Cowan http://www.ccil.org/~cowan cowan(a)ccil.org
One Word to write them all / One Access to find them,
One Excel to count them all / And thus to Windows bind them.
--Mike Champion
5:13 a.m.
New subject: Documentation on B language?
On 8 Mar 2016, at 19:43, John Cowan
<cowan(a)mercury.ccil.org> wrote:
They may not have been in the very earliest 1.5, but rather in one of the
many 1.5 and 1.6 offshoots (which are documented mostly, if at all,
in unsearchable PDFs), probably spelled inc and dec.
I am reasonably sure that they weren't in MACLISP (SETF is there) and fairly sure
also they were not in InterLisp. They do appear in Lisp Machine Lisp, so I would suspect
that this was how they found their way into CL.
However as soon as macros appeared (sometime shortly after Lisp 1.5 I think) things like
this become so easy to implement (in the usual cases at least: fully-fledged ones are
harder until SETF and its machinery exists, although that itself can be implemented with
macrology) that probably they appeared many times in programs informally before this
without anyone bothering to document them.
--tim
5:09 p.m.
New subject: Documentation on B language?
John Cowan <cowan(a)mercury.ccil.org> writes:
Doug McIlroy scripsit:
My copy of the Algol 68 report says "+:=" and "-:=", so it is
questionable why Ken reversed them, especially since the ambiguity
looks obvious.
Various aspects of the language were borrowed
from PL/I, BCPL and Algol
68. ++ and -- were novel operators. The reversal of Algol's assignment
operators (e.g. -= became =-) was eventually repealed in C.
Algol 68, like Algol 60 and Pascal, used := (pronounced "becomes") for
assignment, and the Algol 68 assignment operators were spelled :+=,
:-=, etc. (pronounced "plus and becomes", "minus and becomes", etc.)
Pre-increment operators were already known in Lisp 1.5
long before;
they are now spelled incf and decf in Common Lisp.
AFAICS Algol didn't have them, but every Pascal I know had inc and dec.
--
Christian Neukirchen <chneukirchen(a)gmail.com> http://chneukirchen.org
5:29 p.m.
New subject: Documentation on B language?
Note that the novelty isn't that it adds or subtracts one with storage, but that it
can be used in a more complex expression, along with a pre- and post-evaluation semantics.
Also, Pascal post dates B.
I offer this just as a clarification of the facts. I greatly admire both the languages of
Thompson and Ritchie and those of Prof Wirth. I write a good bit of C code but all things
being equal I would be programming in Oberon. But B's ++ and -- operators seem to be
unique.
Sent from my iPad
On Mar 9, 2016, at 6:09 AM, Christian Neukirchen
<chneukirchen(a)gmail.com> wrote:
John Cowan <cowan(a)mercury.ccil.org> writes:
Doug McIlroy scripsit:
My copy of the Algol 68 report says "+:=" and "-:=", so it is
questionable why Ken reversed them, especially since the ambiguity
looks obvious.
Various aspects of the language were borrowed
from PL/I, BCPL and Algol
68. ++ and -- were novel operators. The reversal of Algol's assignment
operators (e.g. -= became =-) was eventually repealed in C.
Algol 68, like Algol 60 and Pascal, used := (pronounced "becomes") for
assignment, and the Algol 68 assignment operators were spelled :+=,
:-=, etc. (pronounced "plus and becomes", "minus and becomes", etc.)
Pre-increment operators were already known in
Lisp 1.5 long before;
they are now spelled incf and decf in Common Lisp.
AFAICS Algol didn't have them, but every Pascal I know had inc and dec.
--
Christian Neukirchen <chneukirchen(a)gmail.com> http://chneukirchen.org
3209
days inactive
3210
days old
6 comments
6 participants
participants (6)
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Andru Luvisi -
Brantley Coile -
Christian Neukirchen -
Doug McIlroy -
John Cowan -
Tim Bradshaw