From the documentation:

   This Algol 60 interpreter is based upon the "Revised Report on the
Algorithmic Language Algol 60" [RRA60].

   At school, a long time ago, I learned Algol 60 in a completely
theoretical manner.  Later I learned Algol 68 and C (and more ...).

   The concept of call-by-name never left my mind, and so I started to
write this Algol 60 interpreter:  Made for fun and a call-by-name.