ftrain

;; I have 
(def events ["== A ==" "=== A.1 ===" "* One" "* Two" "** Two.A" "** Two.B" "== B =="])

;; (i.e. wikipedia markup) And what I want is:

;; (("== A ==" 
;;    ("=== A.1 ===" 
;;      ("* One" 
;;        "* Two" 
;;        ("** Two.A" 

ftrain

#!/bin/bash
#
#                  _     _  __
#  __ _  __ _ _ __| |__ (_)/ _|_   _
# / _` |/ _` | '__| '_ \| | |_| | | |
#| (_| | (_| | |  | |_) | |  _| |_| |
# \__, |\__,_|_|  |_.__/|_|_|  \__, |
# |___/                        |___/
#
#

ftrain

;; simplest fold definition
(define (fold f init l)
  (if (null? l) init (fold f (f init (car l)) (cdr l))))

;; by this time you are almost certainly comfortable with signatures like:

;; Int -> Int
(fold + 0 '[1 2 3 4 5])
;; => 15

ftrain

(def date-parsers [nil (java.text.SimpleDateFormat. "yyyy") (java.text.SimpleDateFormat. "yyyy-M") (java.text.SimpleDateFormat. "yyyy-M-dd")])

(def grains [:decade :year :month :day]) ;; what's decade doing?

(map #(let [[_ year month day] (re-find #"(\d{2,4})[-_]([\dx]{2})[-_]([\dx]{2})" %)
            date (first (split-with (partial not= "xx") [(if (= (count year) 2) (str "19" year) year) month day]))]
        [(.parse (parsers (count date)) (clojure.string/join "-" date)) (grains (count date))])
     ["thefilehasaname__1939-xx-01.mp3"
      "thefilehasaname__39_01_01.mp3"
      "thefilehasaname__39-01-01.mp3"