Memory-efficient Cartesian products on heterogeneous collections.
This module is a proof-of-concept to propose memory-efficient views on collections.
This is a specific alternative to
combinations, that focuses only highly efficient
Cartesian products between collections of different types.
Collection[Int] X Collection[String] -> Collection[(Int,String)]
However, in Nit, there in no native tuple type. So we need a first building block, a pair.