>Algol-68 (or derivatives of) did rise to some prominence in one place – the USSR. The most prominent implementation of the language came from Leningrad State University. It was apparently used to design Russian telephone exchanges.
6-pass compiler for Algol-68 :) The telephone exchange was built on the base of the microcomputer (while developed in USSR/Russia, and ultimately that microcomputer was mostly used by the Russian military, the major customer for the exchange who funded the work at some point was Alcatel) which was like Tandem, only 3 instead of 2 systems in parallel because of low quality of electronics, the CPU was USSR-developed "Samson" [1], a kind of Elbrus offshoot. The exchange software was developed in SDL (Z.100, kind of like Erlang-by-European-commitee-in-1980ies) and compiled into Algol-68 which was compiled into that CPU codes.
6 passes seems like a lot but likely that was just to fit it in the tiny computers of the time.
One problem with the language is that you can't parse declarations and expressions until after you have parsed the bracket structure of the language (because you can't tell whether a name is a type or an operator until you have processed their declarations (which do not have to be done before use) - that sort of means you have to do at least 2 lexical/parse passes
6-pass compiler for Algol-68 :) The telephone exchange was built on the base of the microcomputer (while developed in USSR/Russia, and ultimately that microcomputer was mostly used by the Russian military, the major customer for the exchange who funded the work at some point was Alcatel) which was like Tandem, only 3 instead of 2 systems in parallel because of low quality of electronics, the CPU was USSR-developed "Samson" [1], a kind of Elbrus offshoot. The exchange software was developed in SDL (Z.100, kind of like Erlang-by-European-commitee-in-1980ies) and compiled into Algol-68 which was compiled into that CPU codes.
[1] (in Russian) https://www.computer-museum.ru/articles/sistemi_kompleksi/90...