[jrevels]

Cool stuff! Thanks for the write-up. Getting broadcast ergonomics right in a fully statically typed context seems both tricky and pretty satisfying.

> We thought it’d be a fun/simple feature and a good break from the heavy duty work on automatic differentiation we had just published

Perhaps it wasn't as much of a break as you might think - funnily enough, static broadcast semantics can serve as an interesting structural foothold for certain AD optimizations [1]

(disclaimer: I'm a coauthor on that paper :) but it's been quite a while since I've done work in the AD space)

[1] https://arxiv.org/pdf/1810.08297