// file:   number.rex
// author: Robert Keller

// number numbers the elements of any list, starting with 0.  The number
// elements are returned as a pair [element, index]

number(List) = number(List, 0);


// number(L, N) numbers the elements of list L starting with N

number([], N) => [];

number([A | L], N) => [[A, N] | number(L, N+1)];