I came away with a similar reaction, but there is no need to map separately first: https://news.ycombinator.com/item?id=13136056 https://news.ycombinator.com/it

I came away with a similar reaction, but there is no need to map separately first: https://news.ycombinator.com/item?id=13136056 https://news.ycombinator.com/item?id=13136056 Sometimes I do wish Erlang had something like F#'s active patterns because it'd make this sort of thing trivial to add to standard pattern expressions. Maybe someday I'll figure out how to add it myself.