Not sure what you count as higher order abstractions, but lparallel, fset, cl-ppcre and other libraries make use of compiler macros; this is relevant w.r.t. efficiency.
Haxl is modern. Ponylang's concurrency is modern. Rust's concurrency is modern.
lparallel and fset's affordances are not. I'm not sure why a single threaded regular expression compiler is mentioned here.
I'd have to check. Is fset even using the current standard (not the newest stuff) for immutable-friendly data structures? Last time I checked they had used a lot of older stuff from Okasaki's work and much of that has been improved upon substantially now.
Even Clojure is out of date, compared to this year's innovations!
