Speaking as a person that worked on the original Mac OS, the "story" that the OS was originally based on Pascal is not really correct. It was written in Assembly, with the belief that later developers would be using Pascal, and so Apple wrote the developer facing Inside Macintosh with Pascal as the language used for the examples. However, as far as I know no major software houses seriously worked in Pascal on the Mac; C and Assembly were the kings during the 80's and continued with C/C++ during the 90's.
Mac OS used Pascal strings rather than C's null-terminated strings (Inside Macintosh volume 1, p90 -- Using assembly language / Calling conventions -- "Pointer to string (first byte pointed to is length byte)" https://vintageapple.org/inside_o/pdf/Inside_Macintosh_Volum...
They were an absolute pain to switch between when writing C code for Mac OS, and are evidence of the Mac OS designers having Pascal on the brain when designing the OS, not just their choice of example language in the documentation.
> as far as I know no major software houses seriously worked in Pascal on the Mac
Adobe Photoshop for the Macintosh was written in Pascal:
Yeah, I remember. The string issue was easily fixed by simply placing a null at the end of one's strings and maintaining a Pascal string pointer for OS traps and using the C string pointer for everything expecting C strings.
I still have a work-in-progress mimeographed and hand written copy of Inside Macintosh that was used by the original 3rd party developers, back when a good 2/3rds of the OS was still being completed.
As far as I understoond by several interviews, and podcasts, that I cannot now refer to, MPW and the whole migration from Object Pascal and App Toolbox into C and C++, was a kind of submarine project from a couple of folks that weren't into Object Pascal.
As they succeeded, MPW came to be, followed later by the partnership with Metrowerks and their PowerPlant C++ framework.
The point is, back then you didn't end up writing nice software because your language was awesomer than other languages. You wrote nice software by escaping to assembly, so support for that was important for state of the art tools.
Yeah, and while both ecosystems allowed for using external and inline Assembly tools, C only had inline assembly keyword (and nothing else beyond that) as part of ISO C89, a couple of years later after 1972, usually it is only pointed out as negative when Pascal based applications reach out to it.
Another thing that usually escapes, is that actually writting cool games on any 16 bit home computers, required the full deck of tricks of Assembly programming, neither C nor Pascal dialect were up to the job, with the first two decades of their existence.
Even arcade systems like Midway Games units, used mostly Assembly, despite their TMS34010 having a C SDK available.
