This package contains a set of primitives and combinators for event patterns. Example:
import qualified Prelude as P
let sundays = every 2 sunday
let today = (YearMonthDay 2013 12 01)^.from gregorian
P.take 2 $ instancesFrom today sundays
[2013-12-08, 2013-12-22]
Hackage: http://hackage.haskell.org/package/time-patterns
License: BSD3, see LICENSE file