Fri Jan 30 15:21:28 EST 2015

Functional vs. Mutation

So for the logic analyzer, and important question is to use in-place
update or not.

Is a rust "fold" smart enough to use in-place update for an object
that stays mostly the same?

It seems that even if the fold would be smart enough to take care of
performance concerns, there is still the element that a mutating
algorithm is a lot easier to read and write (less code!).

I think (hearsay) this is also part of what Lens is doing for Haskell:
provide a mutable interface for small updates.