An IndexMaker takes some input of type I and returns an Index whose
elements are of type O.
The basic use case is to take a TupleN of Seq-like instances and
return an Index whose entries are instances of TupleN corresponding
to the elements of the original Seqs.
An IndexMaker takes some input of type I and returns an Index whose elements are of type O.
The basic use case is to take a TupleN of Seq-like instances and return an Index whose entries are instances of TupleN corresponding to the elements of the original Seqs.
Type of input with which to make index
Type of contents of output index