Problem Statement

Create a function,   or show a built-in function,   to count the number of non-overlapping occurrences of a substring inside a string. The function should take two arguments:

It should return an integer count. The matching should yield the highest number of non-overlapping matches. In general, this essentially means matching from left-to-right or right-to-left   (see proof on talk page).

Let's start with the solution:

countOccurrences: function [str, substr]-> size match str substr

loop [["the three truths" "th"] ["ababababab" "abab"]] 'pair ->
    print [
        ~"occurrences of '|last pair|' in '|first pair|':" 
        countOccurrences first pair last pair
    ]