Re: [Haskell-cafe] Anonymous, Unique Types, maybe

Umm, an obvious point is that if you really are using lists as streams they should appear infinite to the processing code, so you shouldn't encounter operations that fail due to incompatible lengths. Otherwise I think there might be packages on Hackage for fixed sized lists, its a common example for the power of GADTs, though personally I've found size annotated lists unusable at the point where I need `filter` (which you are calling mySelect?).