Johannes Waldmann wrote:
a) ... to use Maybe b) ... to provide my own Data.Heap.View type
leave the choice up to the programmer, and provide a generic interface, accepting any MonadZero (*) instance.
cf. Data.Set.maxView
AFAIK there has been a vivid discussion about that. I think the crux of the matter was that a monad is too general. Either there is a result or there is not. That's precisely the intended use of a Maybe. Besides, I just learned that Data.Map.{lookup,minView,maxView} and the like have been modified to return a Maybe in the current GHC head branch, see [1]. This suggests using Maybe in my case as well.
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[1] http://www.haskell.org/ghc/dist/current/docs/libraries/containers/Data-Map.h... -- Früher hieß es ja: Ich denke, also bin ich. Heute weiß man: Es geht auch so. - Dieter Nuhr