[hwayne]

Since writing this I've been informed of some gaps (mostly through email and a lobsters [1] thread). Some of the main ones:

- McCarthy's "Direct Union" is probably conflating "disjoint union" and "direct sum".

- ML probably got the sum/product names from Dana Scott's work. It's unclear if Scott knew of McCarthy's paper or was inspired by it.

- I called ALGOL-68 a "curious dead end" but that's not true: Dennis Ritchie said that he was inspired by 68 when developing C. Also, 68 had exhaustive pattern matching earlier than ML.

- Hoare cites McCarthy in an earlier version of his record paper [2].

Also I kinda mixed up the words for "tagged unions" and "labeled unions". Hope that didn't confuse anybody!

[1] https://lobste.rs/s/ppm44i/very_early_history_algebraic_data...

[2] https://dl.acm.org/doi/10.5555/1061032.1061041