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:

;; from Racket
(define count-substring
   (compose length regexp-match*))

(count-substring "aab" "graabaabdfaabgh") ;; substring
    → 3
(count-substring "/ .e/" "Longtemps je me suis couché de bonne heure") ;; regexp
    → 4