[Haskell-cafe] Importance of identity element in finger trees?

[Daniel Peebles]

Hi all,

I was looking at finger trees and the tricks for getting priority
queues out of them seemed a little hackish, with a distinguished
infinity element or maxBound. But it seems (although I have not yet
tried it) like in many cases the monoid's identity element wouldn't be
necessary (a bit like the difference between fold* and fold*1). Could
a finger tree be applied to an arbitrary semigroup? Or is the identity
more fundamental than it looks?

Thanks,
Dan