Our string type is an OCaml string

cuts sep str separates str into multiple substrings, stripping out the separating character sep. String.concat "/" (String.cuts '/' xs) is the identity.

cut sep str cuts the string str at the first occurence of sep into its left and right parts. If sep is not found, None is returned. If Some (a, b) is returned, a ^ sep ^ b is equal to str.

is_prefix ~prefix str is true if str begins with prefix, false otherwise.

is_suffix ~suffix str is true if str ends with suffix, false otherwise.

slice ~start ~stop str slices str into a smaller piece, starting at offset start (default 0), ending at stop (default String.length).

to_lower str converts all printable ASCII characters to lowercase.

is_ascii ~p str is true if all characters in str are ASCII characters: 0-9, a-z, A-Z OR satisfy p. Otherwise false.

trim str removes leading and trailing whitespaces of str.

get str offset retrieves the character at offset in str.

concat sep xs concatenates all xs, using sep as separator.

compare a b compares a with b using String.compare.

length str is the byte length of str.

compare_insensitive a b first converts a and b to lowercase strings, then uses compare.

equal a b is String.equal a b.