let matrix_of_string (s : string) : string array array = let rows : string list = String.split_on_char '\n' s in let utf8_rows : string list list = List.map UTF8_segmenter.utf_8_grapheme_clusters rows in let utf8_arrays : string array list = List.map Array.of_list utf8_rows in Array.init (List.length utf8_arrays) (List.nth utf8_arrays)