ruby is a poor abstraction AND inefficient. text based manipulations and crap like IFS are terrible abstractions. languages like standard ML were made SPECIFICALLY for abstracting. they literally were meticulously designed to provide proper abstractions (think, for example how the elements of a union type are abstract objects, and can be built up to model coherent ideas, while in ruby any variable probably requires a lookup at runtime in ascii^Wunicode^wunicode-minus-whatever-feature-was-found-to-be-harmful-in-this-context)

what im saying is that the academic idea of abstraction is far better and less leaky than ruby (dynamic name resolution and such "scripting language" crap) or java (data structures are intended to be used once or twice per program (exaggerating) instead of fluently like you would make trees in a functional language); its just obscured but if everyone understood the motivation it would have replaced stuff like ruby in all use cases.

i see ruby and java as a little shop where the owner will let you instantiate one or two objects according to some terms, and then let you maybe make your own class, but it will essentially just be a wrapper around a few of the shop's objects. whereas in ML you can model anything from the ground up, even numbers, and it will still be nicely implemented and the abstractions will be almost perfect.