Ah but “functor,” is a name from category theory and algebraic topology. I had read along thinking that this would come up in the conclusion! Instead it seems i

Ah but “functor,” is a name from category theory and algebraic topology. I had read along thinking that this would come up in the conclusion! Instead it seems it’s not even mentioned in the sources for the name. There’s potentially something like this in the “esqueleto” package for Haskell. But it has some limitations. It composes on syntactic fragments. Although speaking of functors, the category theory ones, maybe categorical databases would fit the bill: https://categoricaldata.net/ https://categoricaldata.net/