@sree Thank you for that suggestion! The question from @lindsey sent me on my own dusty filing cabinet rummage, and I dug out our copy of "Design Considerations for a Functional Programming Language" by Rod Burstall from 1977. This is the paper that introduced NPL, a predecessor to Hope and hence to Haskell; it's an early published source for algebraic datatypes and pattern matching, and also for list comprehensions. When I have time, I intend to write a blog post about it. I couldn't find it anywhere else online, so it is now at https://archive.org/details/burstall-design-considerations-for-a-functional-programming-language