Henning Thielemann wrote: >> is there a monad transformer to consume an input list? I've got external >> events "streaming into the monad" that are consumed on demand and I'm >> not sure if there's something better than a StateT. > > I wondered that, too. I wondered whether there is something inverse to > Writer, and Reader is appearently not the answer. Now I think, that > State is indeed the way to go to consume a list. Even better is StateT > List Maybe: > > next :: StateT [a] Maybe a > next = StateT Data.List.HT.viewL -- see utility-ht package >
But a StateT provides the power to modify the list in other ways than reading the first element (modify (x:)). Maybe ParsecT is closer to what I'm looking for ;) -- Früher hieß es ja: Ich denke, also bin ich. Heute weiß man: Es geht auch so. - Dieter Nuhr _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
