> Only if you are talking about UCSD Pascal on the early Apple systems I'm not. If you aren't familiar, take a look at the original edition of Inside Macintosh

> Only if you are talking about UCSD Pascal on the early Apple systems I'm not. If you aren't familiar, take a look at the original edition of Inside Macintosh, particularly the "summary" sections (e.g. page 213 of the PDF for QuickDraw): https://vintageapple.org/inside_o/pdf/Inside_Macintosh_Volume_I_1985.pdf https://vintageapple.org/inside_o/pdf/Inside_Macintosh_Volum... Notice that all of the definitions are written as Pascal data types and function definitions. > AppToolbox exists and has required for all Mac systems since the classic model. The "Toolbox" was a general term for Apple's ROM and system routines. It did not refer to a specific programming language or development environment. (See page 21 of the PDF linked above for a definition.) > It was later on replaced by the C++ version when MPW was introduced, and all the plain C like functions, where actually C++ under the hood with extern "C". This is not accurate. Apple never "replaced" the Toolbox routines in classic Mac OS - they were called from C instead of Pascal as developers shifted to that language, but the routines all remained the same (often still using Pascal data types for types like strings, as I mentioned earlier). There was never any official C++ interface to the Toolbox.