Clojure was also the first mainstream (non-PF) language to implement Okasaki's as first class data structures. I know Scala quickly followed suit, since I reme

Clojure was also the first mainstream (non-PF) language to implement Okasaki's as first class data structures. I know Scala quickly followed suit, since I remember Odersky bragging in a meetup that he went out of his way to find the scientists that improved on Okasaki's work and based Scala's data structures on their work instead.