A bit more on this. csh(1) was wrtten around 1978 and yes # as a comment was only for scrtipts, think it was why would you need to comment interactively? And the # as an addition to be a comment in Bourne shell had to be around 1980 as that is when Dennis Ritchie added #! to exec(2) in the kernel. From this point on this forced all UNIX scripting languages to use # as a comment as it just exec'd the first string after the #! with the name of the current file being exec'd as the single argument. So things like perl(1) and python(1) had to use # if they wanted the #! mechanism to work for them too. So this worked great for shell scripts, it didn't work for awk(1) nor sed(1) nor s(1)(that is R(1) now) scripts (all needed a -f for input from file) nor dc(1) scripts as dc had no comment character. While Research UNIX got !# in 1980, this was after the 7th Edition release and the 8th Edition wasn't released until 1985), BSD got it around 1982-83, and System V didn't implement it until 1988. Eventully #! was extented so #!/usr/bin/awk -f would work. Also Bill Joy was the first to use # as a comment character in an /etc config file for his /etc/ttycap (which became /etc/termcap) for vi(1). Most configs did not have a comment at all at that time, while /etc/master used a * as a comment (SCCS used * as a comment too btw) Also before you say wait! ALGOL uses # as comment and is older than Kernighan' ratfor(1). This is a later addition. The original used the EBCDIC cent sign character to start and another cent sign to end the comment (i.e. programmer's two cents). If you were on an ASCII system this became "co" (for comment) as the original ASCII does not have a cent sign -Brian
On Mon, 6 Jan 2020, Brian Walden wrote: > csh(1) was wrtten around 1978 and yes # as a comment was only for > scrtipts, think it was why would you need to comment interactively? Why would you *not* want to? You've just made "#" asymmetric in its behaviour; in the meantime the parser just sees an unescaped "#" and ignores everything after that, without regard to context. You might also be using "script" e.g. script blah blah # Now here I do something funky *really* funky stuff ^D [...] > Also before you say wait! ALGOL uses # as comment and is older than > Kernighan' ratfor(1). [...] Funny; I recall ALGOL using "comment ... ;" or was that ALGOLW (which I loved using; I wish I still had my ALGOLW book)? -- Dave
[-- Attachment #1: Type: text/plain, Size: 1019 bytes --] On Mon, Jan 6, 2020 at 3:51 PM Dave Horsfall <dave@horsfall.org> wrote: > On Mon, 6 Jan 2020, Brian Walden wrote: > > > csh(1) was wrtten around 1978 and yes # as a comment was only for > > scrtipts, think it was why would you need to comment interactively? > > Why would you *not* want to? You've just made "#" asymmetric in its > behaviour; in the meantime the parser just sees an unescaped "#" and > ignores everything after that, without regard to context. > > You might also be using "script" e.g. > > script > blah blah > # Now here I do something funky > *really* funky stuff > ^D > Or you might have cut and paste the commands from a script to test something, or to redo something by hand that failed for some reason. Warner > [...] > > > Also before you say wait! ALGOL uses # as comment and is older than > > Kernighan' ratfor(1). [...] > > Funny; I recall ALGOL using "comment ... ;" or was that ALGOLW (which I > loved using; I wish I still had my ALGOLW book)? > > -- Dave > [-- Attachment #2: Type: text/html, Size: 1675 bytes --]
[-- Attachment #1: Type: text/plain, Size: 544 bytes --] On Mon, Jan 6, 2020 at 5:51 PM Dave Horsfall <dave@horsfall.org> wrote: > Funny; I recall ALGOL using "comment ... ;" or was that ALGOLW (which I > loved using; I wish I still had my ALGOLW book)? > Algol-W From, the Sites book, (Page 10, Section 1 'Terminology) [Dave, I'll send you the PDF offline]. The symbol *comment* followed by any sequence of characters not -containing semicolons, followed by a semicolon, is called a *comment*. A comment has no effect on the meaning of a program, and is ignored during execution of the program. [-- Attachment #2: Type: text/html, Size: 1774 bytes --]
[-- Attachment #1: Type: text/plain, Size: 598 bytes --] On Tue, 7 Jan 2020, Clem Cole wrote: > Algol-W From, the Sites book, (Page 10, Section 1 'Terminology) [Dave, > I'll send you the PDF offline]. For the record, it was received OK; thanks! > The symbol comment followed by any sequence of > characters not -containing semicolons, followed by a > semicolon, is called a comment. A comment has no > effect on the meaning of a program, and is ignored > during execution of the program. For the benefit of the OP, here is no mention of "#" being a comment in ALGOL(W). -- Dave
> On Jan 6, 2020, at 2:51 PM, Dave Horsfall <dave@horsfall.org> wrote:
>
> On Mon, 6 Jan 2020, Brian Walden wrote:
>
>> Also before you say wait! ALGOL uses # as comment and is older than Kernighan' ratfor(1). [...]
>
> Funny; I recall ALGOL using "comment ... ;" or was that ALGOLW (which I loved using; I wish I still had my ALGOLW book)?
In Algol68 # ... # is one of the forms for block comments!
On Tue, 7 Jan 2020, Bakul Shah wrote:
> In Algol68 # ... # is one of the forms for block comments!
Interesting... All we had at university though was ALGOL W (as far as I
know; there were several languages that mere students could not use, such
as FORTRAN H).
-- Dave
[-- Attachment #1: Type: text/plain, Size: 774 bytes --] At Mon, 6 Jan 2020 17:39:39 -0700, Warner Losh <imp@bsdimp.com> wrote: Subject: Re: [TUHS] # (was Re: sh: cmd | >file) > > > Or you might have cut and paste the commands from a script to test > something, or to redo something by hand that failed for some reason. Cut & Paste? Most of us couldn't do that until the very late 1980's at earliest! The poor man's cut&paste was to do something like 'sed -n 3,9p script | sh', but I don't think I ever did that with csh in the days when a '#' comment was for scripts only, so I don't know if old csh treated a pipe on stdin as a script or not. -- Greg A. Woods <gwoods@acm.org> Kelowna, BC +1 250 762-7675 RoboHack <woods@robohack.ca> Planix, Inc. <woods@planix.com> Avoncote Farms <woods@avoncote.ca> [-- Attachment #2: OpenPGP Digital Signature --] [-- Type: application/pgp-signature, Size: 195 bytes --]
Dave Horsfall wrote: >On Tue, 7 Jan 2020, Bakul Shah wrote: > >> In Algol68 # ... # is one of the forms for block comments! > >Interesting... All we had at university though was ALGOL W (as far as I >know; there were several languages that mere students could not use, such >as FORTRAN H). Yes, but when was it implemented? Kernighan is first ever if it is not before 1974. So I decided to look and it took me down a rabbit hole of ALGOL taht leads back to Bourne shell and then right back to # (but in C) By reading the ALGOL 68 wiki page, the laguange seemed to have had a character set problem since day one, and it seems if you didn't have the cent-sign you were to use PR for pragmat for comments. And since it had problems it was continually extened. I just cant find when # was defined. I looked at various old implementations (none pre 1974 list #) -- - CDC's ALGOL 68 compiler from 1975 you could only use use PR .. PR (both # and CO were not defined) http://www.bitsavers.org/pdf/cdc/Tom_Hunter_Scans/Algol_68_version_1_Reference_Manual_RevB.pdf - The official revised ALGOL86 spec from 1978 lists all these ways to enter them (bottom of page 112) in this order -- brief comment symbol: cent-sign bold comment symbol: comment style 1 comment symbol: co style 2 comment symbol: # bold pragmat symbol: pragmat style 1 pragmat symbol: pr seeing # is "style 2" it looks like a later extention to me http://www.softwarepreservation.org/projects/ALGOL/report/Algol68_revised_report-AB.pdf - ALGOL68/19 from 1975 list these 4 symbols as comments: # % co pr http://www.softwarepreservation.org/projects/ALGOL/manual/Gennart_Louis-Algol_ 68_19_Reference_Manual.pdf - DECs ALGOL (1976 printing but first released was 1971) for system10 uses a ! for a comment as # means "not equal" -- http://www.bitsavers.org/www.computer.museum.uq.edu.au/pdf/DEC-10-LALMA-B-D%20 decsystem10%20ALGOL%20Programmer's%20Reference%20Manual.pdf - CMU's ALGOL68S from 1978 list all these ways -- co comment comment comment pr pragmat pragmat pragmat # (comment symbol) comment :: (pragmat symbol) pragmat (its for UNIX v6 or v7 so not surprising # is a comment) http://www.softwarepreservation.org/projects/ALGOL/manual/a68s.txt/view - Rutgers ALGOL 68 interprter from 1987 for UNIX does not implement PR nor PRAMAT and says comments are # CO or COMMENT https://www.renyi.hu/~csirmaz/algol-68/linux/manual I could not find a freely accessible manual for ALGOL68R (very 1st one) nor Cambridge's ALGOL68C. What's intresting here is Stephen Bourne was on the team that made ALGOL68C before he move to Bell Labs. It'd be pretty funny if he implemented a language that there were 7 or 8 ways to enter a comment (cent, co, comment, pr, pragmat, #, ::, %) yet there were zero ways to enter a comment in the Bourne shell. Also the style of "COMMENT put a note here COMMENT" is very un-ALGOL like (with DO .. OD, IF .. FI) shouldn't it be like this? COMMENT put a note here TNEMMOC CO put a note here OC PRAGMAT directive here TAMGARP PR directive here RP So then I remembered Bourne used the C preprocssor to make C like ALGOL when he wrote the shell. If you've never seen it, his C looks like this -- case TSW: BEGIN REG STRING r = mactrim(t->swarg); t=t->swlst; WHILE t DO ARGPTR rex=t->regptr; WHILE rex DO REG STRING s; IF gmatch(r,s=macro(rex->argval)) ORF (trim(s), eq(r,s)) THEN execute(t->regcom,0); t=0; break; ELSE rex=rex->argnxt; FI OD IF t THEN t=t->regnxt FI OD END break; ENDSW So I wanted to see if he remapped C comments /* */ I am not even sure you could even do that with the C preprocessor but took alook anywy and in https://minnie.tuhs.org/cgi-bin/utree.pl?file=V7/usr/src/cmd/sh/xec.c It's first lines are this -- # /* * UNIX shell * * S. R. Bourne * Bell Telephone Laboratories * */ #include "defs.h" #include "sym.h" So nope, just regular C comments (which came from PL/I btw which was what multics was programmed in) But look! The very first line of that file! It is a single # sitting all by itself. Why? you ask. Well this is a hold over from when the C preprocessor was new. C orginally did not have it and was added later. PL/I had a %INCLUDE so Ritchie eventaully made a #include -- but pre 7th Edition the C preprocessor would not be inkoved unless the very first character of the C source file was an # Since v7 the preprocessor always run on it. The first C preprocessor was Ritchie's work with no nested includes and no macros. v7's was by John Reiser which added those parts. that 1st line with a single # sitting by itself reminds me of the csh construct as well. -Brian
> On Jan 7, 2020, at 9:20 PM, Brian Walden <tuhs@cuzuco.com> wrote: > > Dave Horsfall wrote: >> On Tue, 7 Jan 2020, Bakul Shah wrote: >> >>> In Algol68 # ... # is one of the forms for block comments! >> >> Interesting... All we had at university though was ALGOL W (as far as I >> know; there were several languages that mere students could not use, such >> as FORTRAN H). > > Yes, but when was it implemented? Kernighan is first ever if it is not > before 1974. So I decided to look and it took me down a rabbit hole of > ALGOL taht leads back to Bourne shell and then right back to # (but in C) Tanenbaum’s “A tutorial on Algol 68” published in Computing Surveys, June 1976 mentions that # is one of the (four) ways a comment may be enclosed. https://research.vu.nl/ws/portalfiles/portal/74119499/11057 An earlier paper “Algol68 with fewer tears” by C H Lindsey, 1972 also mentions # as an alternate symbol. https://academic.oup.com/comjnl/article-pdf/15/2/176/1002964/15-2-176.pdf