Comment by int_19h

Algol 60 is also ... not exactly the easiest language to compile, even today. Here's the spec:

https://www.masswerk.at/algol60/report.htm

Call by name in particular can be very tricky, especially where it intersects with higher-order functions.

It can also be interesting to read contemporary discussions of problematic spots in the language, e.g.:

https://dl.acm.org/doi/10.1145/366193.366209

https://dl.acm.org/doi/10.1145/363717.363743

And the original ALGOL bulletin which has committee reports and mailing lists for the design process:

https://archive.computerhistory.org/resources/text/algol/alg...