Compilers and languages (Was: Help reading a 9 track tape

[Gavin Scott]

On Mon, Aug 2, 2021 at 6:07 PM Fred Cisin via cctalk
<cctalk at classiccmp.org> wrote:

> One of the rites of passage (not necessarily the only one) in "computer
> science" education is that every grad student invents a new language, and
> writes a compiler.  The compiler is not considered finished until the
> current iteration of that compiler was written in that language and
> compiled by that iteration of the compiler.

It's an interesting language classification as to whether the primary
/ reference implementation of the language is written in itself or
not. For example, the primary Python implementation is CPython written
primarily in C, and Java is primarily C++ (certainly both have
substantial libraries that are written in the language however, and
there exist implementations of both that are written in themselves I
believe like PyPy for Python).

For languages that aren't written in themselves it means that some of
the core language developers may primarily be C/C++ programmers which
might have some impact on the language's design and/or implementation.

Another interesting question is whether the currently shipping version
of a language written in itself was compiled using the same version of
itself or the previous version. I recall HP compilers generally being
built with the previous version (at least the last time I looked which
was probably in another century).