The original Mac was written in Pascal and assembly, though not natively. They had to use a cross-platform development system called the Macintosh Development System, compiling on one machine and transmitting the binary to the target (via a serial connection) for execution and testing. Very similar in concept to hardware-testing software on iOS. //

The Lisa/Lisa 2 supported this kind of cross-platform development, but it was too expensive for most developers. The environment sold to developers comprised two Mac 128s. When the 512 came out, it became possible to code natively. Two or three applications were available by late 1984 that allowed users to write and run simple interpretive code: Microsoft Basic, Turbo Pascal, and a Mac version of Apple Pascal that didn't seem to materialize past the demo stage.

The lack of a good, cheap development system probably contributed to the exodus of developers--especially game developers--from the Mac to the PC. It wasn't until the Mac Plus came out in 1986 that it was a truly comfortable environment to code in. Two years wasted. Oh, well.