Here’s one way to solve your example, but this is not for an arbitrary number of sequences.
val ints = List(1,2,3)
val chars = List('a', 'b', 'c')
val strings = List("Alpha", "Beta", "Gamma")
val bools = List(true, false, false)
val input = ints zip chars zip strings zip bools
// Flattens a tuple ((A,B),C) into (A,B,C)
def f2[A,B,C](t: ((A,B),C)) = (t._1._1, t._1._2, t._2)
// Flattens a tuple ((A,B),C,D) into (A,B,C,D)
def f3[A,B,C,D](t: ((A,B),C,D)) = (t._1._1, t._1._2, t._2, t._3)
input map f2 map f3
I don’t think it is possible to do it generically for tuples of arbitrary length, at least not with this kind of solution. Tuples are strongly-typed, and the type system doesn’t allow you to specify a variable number of type parameters, as far as I know, which makes it impossible to make a generalized version of f2 and f3 that takes a tuple of arbitrary length ((A,B),C,D,...) (that would return a tuple (A,B,C,D,...)).
If there were a way to specify a variable number of type parameters, we wouldn’t need traits Tuple1, Tuple2, … Tuple22 in Scala’s standard library.