Comment by senfiaj
7 hours ago
But once you have written in assembly, you could start to write the next version in the higher level language. The first version (written in assembly) doesn't necessarily have to produce the most optimal code, just good enough and correct. Most of the improvements can be done in the self hosted compiler (in a higher level language). So this period did not have to last many years.
I am sure writing a self-hosted Fortran compiler is possible, but it wouldn’t be my first choice for writing a Fortran compiler, even given the Fortran of today.
In the 1970s, it would have been really low on my list, likely below using a macro assembler.