C.mmp Algol68sImplementation of programming language Algol68
Wikipedia: ALGOL 68S was designed as a subset of ALGOL 68 in order to permit single-pass compilation. It was mostly for numerical computation.
A compiler for ALGOL 68S was available for the PDP-11, written in BLISS. The multiprocessor version designed for the C.mmp has been preserved at the PUPS archive of the PDP11 Unix Heritage society