Is Elm using a particular library for its persistent structures, or are they custom for Elm? I've read that it has both List and Array, yet neither appears to

Is Elm using a particular library for its persistent structures, or are they custom for Elm? I've read that it has both List and Array, yet neither appears to be ideal for proper functional programming; List, as you say, is a linked list, yet it is recommended [0] over Array for functional operations like map, fold, etc -- but you wouldn't normally want linked lists for that sort of thing, esp. if your maps and folds were part of a larger data transformation of composed functions. Does Elm offer anything similar to the structure of ClojureScript's persistent vector? I have learned that FP without the guts of serious persistent structures is not so good in practice. [0] https://stackoverflow.com/questions/37707577/array-vs-list-in-elm#comment67060087_37707812 https://stackoverflow.com/questions/37707577/array-vs-list-i...