He must be referring to https://dl.acm.org/doi/pdf/10.1145/2935323.2935331 ?

Just looking at refs for the moment: Henglein and Hinze's discriminators are interesting, whenever you come back up for air. (are they also amenable to sorting codata?)

The oft-cited R Bernecky is, IIRC, also known as "Boolean Bob" for his SWAR-style algos. EDIT: nope, confused him with R Smith: https://aplwiki.com/wiki/Bob_Smith

(I once asked Boolean Bob if any of his tricks went back to the card processing days —I could even believe the keyed tree* might?— but he was too young to know, and the people he'd have liked to ask are no longer available.)

EDIT: Aardappel also has some interesting languages: https://strlen.com/#programming-languages

* for manipulating Bills of Materials despite the linearity of card decks?

EDIT2: compare "§3.2.1 Constructing Node Coordinates" (p34) with [T in "Table 1.19 Full list matrices of the tree of Fig. 1.16" in A Programming Language (p50): https://archive.org/details/aprogramminglanguage1962/page/n6...

[all three appear to be 1-origin, probably due to the phenomenon mentioned in the footnote on p49 of APL]

Flattening ASTs and other compiler data structures (2023)