Stream (computer science)

In type theory and functional programming, a stream is a potentially infinite analog of a list, given by the coinductive definition:
data Stream α = Nil | Cons α (Stream α)
Generating and computing with streams requires lazy evaluation, either implicitly in a lazily evaluated language or by creating and forcing thunks in an eager language. In total languages they must be defined as codata and can be iterated over using (guarded) corecursion.