Thanks. You inadvertently completely confirm the point that I was seeking to validate.

> You want me to cite compilers that don't compile C that support a C extension ?

No.

There are, hmm, I am not sure, at least 2, probably 3, and I suspect more than 3 assumptions in here.

#0, general context:

The bigger picture here is that there is a whole world of OS and language development which is completely outside the world of Unix, C, and things that derive, directly or indirectly from it.

However, the Unix+C world is so big, so commercially successful, that a lot of people in it can't see that there is anything else. To quote Gaiman and Pratchett, it's the same as the reason that "people in Trafalgar Square can't see England".

I wrote about this recently:
https://www.theregister.com/2022/03/29/non_c_operating_syste...

#1. Plan 9 is not a Unix. It's what came after Unix. As such, I would say it's fair to say that Plan 9 C is not plain ol' Unix C. While the Unix flavour of C has continued on its own path, it's a very conservative path: it's terrified of breaking backwards compatibility. The developers of Plan 9 were not scared like this, and quite cheerfully made big sweeping changes.

#2. So, yes, I would consider that carefully implementing and adding what you yourself call an extension to an existing compiler (or set or family of compilers, it doesn't really matter) is not the same thing as redefining the semantics of a language to say "you are not allowed recursive includes".

One is a big sweeping change; the other is a minor tweak.

#4. The core, important point here is that Plan 9 made significant changes which in places have big ramifications — for instance, performance improvements on the order of several orders of magnitude — simply by tightening up the rules around an existing, well known language. IMHO, adding a new compiler directive is not comparable to this.

Adding a new directive is patching a hole, while changing the rules of how the languages compiled is fixing the design. What I was enquiring about was other designs that fix this problem in the core design of traditional compilers, in other words UNIX C and its descendants.

> And you want the language it compiles to be completely unrelated to C ?

Well, yes! Why not? There are lots of them!

> Frankly, I'd already be quite hard-pressed to even cite a compiler that compiles a language that is completely unrelated to C in the first place and doesn't run on any Unix-like OSes

Really? OK then, let me see how many I can name of the top of my head without googling: Pascal, Lisp, APL, Fortran, Cobol, Algol, BCPL, Forth, Ada, Prolog, Bliss... Okay I'm starting to struggle a little bit now, but I think the point is made.

I wasn't asking for languages that don't run on UNIX. I was asking for languages that weren't built out of UNIX tools. There are legions of languages today that were built pretty much entirely from the existing UNIX toolchain, from Python to JavaScript. My point is that there are dozens to hundreds of languages which are outside of that family.

Plan 9 is, I would argue, outside of that family because it's what came after that family.

Operating systems from outside of the UNIX family? Classic MacOS, AmigaOS, CP/M, MS-DOS, Atari ST TOS, Concurrent CP/M, Concurrent DOS, DR FlexOS, Novell Netware, OS/2 and all of its descendants, GEOS, Palm OS, Newton OS, Microware OS9, Interlisp/Medley, OpenVMS, OpenGenera.

And of course basically all mainframe operating systems... Tools that are still worth billions of dollars today, whose daily use affect everyone who uses a bank account or everyone who ever travels on an aeroplane.

So, yeah, a pretty significant technological and economic market segment… and one that UNIX people often totally forget exists at all. As it seems you did.