[gnulinux]

> The technical primitive data structure here is a hashmap where the keys are sorted.

Why not a tree based map instead?

[The_Colonel]

HashMap and sorted keys sounds like a contradiction. I think they just use "HashMap" as a generic term for "Map" and it's actually a tree based map.

[morelisp]

It is an LSMT, but I cannot imagine why they would need one here.