snap package:Yampa

snap :: SF a (Event a)
Yampa FRP.Yampa FRP.Yampa.EventS
Event source with a single occurrence at time 0. The value of the event is obtained by sampling the input at that time.
snapAfter :: Time -> SF a (Event a)
Yampa FRP.Yampa FRP.Yampa.EventS
Event source with a single occurrence at or as soon after (local) time tEv as possible. The value of the event is obtained by sampling the input a that time.
snapT :: Task a b a
Yampa FRP.Yampa FRP.Yampa.Task
Takes a "snapshot" of the input and terminates immediately with the input value as the result. No time passes; therefore, the following must hold: 
snapT >> snapT = snapT