Re: Block Comments Or Rest-Of-Line Comments?

From	cross@spitfire.i.gajendra.net (Dan Cross)
Newsgroups	comp.lang.c
Subject	Re: Block Comments Or Rest-Of-Line Comments?
Date	2024-03-21 17:58 +0000
Organization	PANIX Public Access Internet and UNIX, NYC
Message-ID	<uthsgp$94j$1@reader1.panix.com> (permalink)
References	<utgjh0$21nsq$2@dont-email.me> <_iXKN.556576$PuZ9.147822@fx11.iad> <86r0g3liii.fsf@linuxsc.com>

Show all headers | View raw

In article <86r0g3liii.fsf@linuxsc.com>,
Tim Rentsch  <tr.17687@z991.linuxsc.com> wrote:
>scott@slp53.sl.home (Scott Lurndal) writes:
>
>> Lawrence D'Oliveiro <ldo@nz.invalid> writes:
>>
>>> The original comment delimiters in C were copied from PL/I:  everything
>>
>> Cite?
>
>Seen in the B language manual:
>
>    Comments are delimited as in PL/I by /* and */.
>
>https://www.bell-labs.com/usr/dmr/www/kbman.html
>
>Note that this style of commenting was not present in
>B's precursor language, BCPL.

It would be appropriate to qualify this statement with some kind
of timeframe as BCPL is still used (albeit not widely, I
assume).

The current version of the language includes `/* ... */` comments
as one of two supported forms:
https://www.cl.cam.ac.uk/~mr10/bcplman.pdf

It appears that this was also present in the 1979 version
described in, "BCPL the language and its compiler" by Martin
Richards:
https://ia803107.us.archive.org/16/items/richards1979bcpl/richards1979bcpl.pdf;
see in particular the lexical analyzer fragment starting on line
127 of page 87.

However, I believe this was not the case at the time that B was
defined.  At least, it is not in the BCPL definition just a
couple of years earlier, despite several years of experience
with PL/1 by then:
https://www.bell-labs.com/usr/dmr/www/bcpl.pdf
Indeed, Dennis Ritchie suggested that some changes to BCPL were
influences taken from C:
https://www.bell-labs.com/usr/dmr/www/bcpl.html

Certainly, both Multics and CTSS BCPL only understand `// ...`,
and those are likely the compilers that Ken Thompson would have
been most familiar with at the time B was created.  E.g.:
https://github.com/dancrossnyc/multics/blob/main/library_dir_dir/system_library_tools/source/bound_bcpl_.s.archive/bcpl_lex1.bcpl#L90

Regarding the original claim, despite OP being a known troll, it
appears to be true.  Dennis Ritchie also mentioned it in his C
history paper: https://www.bell-labs.com/usr/dmr/www/chist.html

As far as I know, PL/I was the first language to use `/*` and
`*/` as comment delimeters.

        - Dan C.

Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar

Thread

Block Comments Or Rest-Of-Line Comments? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-03-21 06:19 +0000
  Re: Block Comments Or Rest-Of-Line Comments? bart <bc@freeuk.com> - 2024-03-21 09:39 +0000
  Re: Block Comments Or Rest-Of-Line Comments? Mikko <mikko.levanto@iki.fi> - 2024-03-21 13:37 +0200
    Re: Block Comments Or Rest-Of-Line Comments? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-03-21 21:16 +0000
      Re: Block Comments Or Rest-Of-Line Comments? David Brown <david.brown@hesbynett.no> - 2024-03-22 10:02 +0100
        Re: Block Comments Or Rest-Of-Line Comments? Blue-Maned_Hawk <bluemanedhawk@invalid.invalid> - 2024-03-22 16:13 +0000
        Re: Block Comments Or Rest-Of-Line Comments? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-03-23 02:58 +0000
          Re: Block Comments Or Rest-Of-Line Comments? "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2024-03-22 21:15 -0700
            Re: Block Comments Or Rest-Of-Line Comments? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-03-23 04:44 +0000
          Re: Block Comments Or Rest-Of-Line Comments? David Brown <david.brown@hesbynett.no> - 2024-03-23 16:24 +0100
            Re: Block Comments Or Rest-Of-Line Comments? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-03-23 18:34 +0000
  Re: Block Comments Or Rest-Of-Line Comments? scott@slp53.sl.home (Scott Lurndal) - 2024-03-21 14:16 +0000
    Re: Block Comments Or Rest-Of-Line Comments? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-21 08:19 -0700
      Re: Block Comments Or Rest-Of-Line Comments? cross@spitfire.i.gajendra.net (Dan Cross) - 2024-03-21 17:58 +0000
        Re: Block Comments Or Rest-Of-Line Comments? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2024-03-22 06:27 -0700
          Re: Block Comments Or Rest-Of-Line Comments? cross@spitfire.i.gajendra.net (Dan Cross) - 2024-03-22 23:16 +0000
  Re: Block Comments Or Rest-Of-Line Comments? Blue-Maned_Hawk <bluemanedhawk@invalid.invalid> - 2024-03-21 14:19 +0000
  Re: Block Comments Or Rest-Of-Line Comments? David Brown <david.brown@hesbynett.no> - 2024-03-21 16:20 +0100
    Re: Block Comments Or Rest-Of-Line Comments? Richard Harnden <richard.nospam@gmail.invalid> - 2024-03-21 16:32 +0000
      Re: Block Comments Or Rest-Of-Line Comments? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-03-21 12:23 -0700
        Re: Block Comments Or Rest-Of-Line Comments? Richard Harnden <richard.nospam@gmail.invalid> - 2024-03-21 19:41 +0000
          Re: Block Comments Or Rest-Of-Line Comments? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-03-21 12:48 -0700
            Re: Block Comments Or Rest-Of-Line Comments? Richard Harnden <richard.nospam@gmail.invalid> - 2024-03-21 19:54 +0000
            Re: Block Comments Or Rest-Of-Line Comments? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-03-21 21:18 +0000
              Re: Block Comments Or Rest-Of-Line Comments? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-03-21 15:50 -0700
        Re: Block Comments Or Rest-Of-Line Comments? scott@slp53.sl.home (Scott Lurndal) - 2024-03-21 20:19 +0000
          Re: Block Comments Or Rest-Of-Line Comments? Kaz Kylheku <433-929-6894@kylheku.com> - 2024-03-21 20:35 +0000
        Re: Block Comments Or Rest-Of-Line Comments? Kaz Kylheku <433-929-6894@kylheku.com> - 2024-03-21 20:22 +0000
          Re: Block Comments Or Rest-Of-Line Comments? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-03-21 15:41 -0700
        Re: Block Comments Or Rest-Of-Line Comments? James Kuyper <jameskuyper@alumni.caltech.edu> - 2024-03-22 12:20 -0400
          Re: Block Comments Or Rest-Of-Line Comments? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2024-03-22 09:33 -0700
          Re: Block Comments Or Rest-Of-Line Comments? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-03-22 23:42 +0000
      Re: Block Comments Or Rest-Of-Line Comments? David Brown <david.brown@hesbynett.no> - 2024-03-22 10:09 +0100
  Re: Block Comments Or Rest-Of-Line Comments? fir <fir@grunge.pl> - 2024-03-21 19:46 +0100
    Re: Block Comments Or Rest-Of-Line Comments? Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-03-21 21:14 +0000
  Re: Block Comments Or Rest-Of-Line Comments? Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2024-03-22 22:50 +0000

csiph-web