I wasn't a mac user until later, are you saying that was done for reasons of ide...

pjmlp · on July 15, 2015

Yes. Mac OS was initially written in a mix of Object Pascal and Assembly.

Even Photoshop 1.0 was, check the available source code.

Object Pascal was the inspiration for Turbo Pascal 5.5 OOP extensions.

After a few OS releases, UNIX was already getting user in the industry and pressure from users about C compiler availability grew.

Apple introduced a new SDK with C and C++ support, including a C++ framework. Afterwards the new OS apis were written in C.

Also by this time, Apple did their first attempt at the UNIX market with A/UX.