According to Wikipedia
Unlike some other macro processors, m4 is Turing-complete as well as a practical programming language.
From the m4 documentation:
The
m4macro processor is widely available on all UNIXes, and has been standardized by POSIX. Usually, only a small percentage of users are aware of its existence. However, those who find it often become committed users. The popularity of GNU Autoconf, which requires GNUm4for generating configure scripts, is an incentive for many to install it, while these people will not themselves program inm4.
I’m not volunteering to create a track for m4, at least not at the moment. I’ve found getting the 8th track up an running very challenging, and I’ve committed myself to an OpenEuphoria track and possibly a SNOBOL4 track. It was in the context of building SNOBOL4 that I noticed that I didn’t have m4 installed and thus this posting.
I get the impression that m4 is still used a fair bit. Any takers?