Clojure pprint table markdown compatible, left aligned.

print_table_2.clj

;   Copyright (c) Rich Hickey. All rights reserved.
;   The use and distribution terms for this software are covered by the
;   Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
;   which can be found in the file epl-v10.html at the root of this distribution.
;   By using this software in any fashion, you are agreeing to be bound by
;   the terms of this license.
;   You must not remove this notice, or any other, from this software.

; this is the same as clojure.pprint/print-table
; but with some options I liked to have

(defn print-table-2
  "Prints a collection of maps in a textual table. Prints table headings
   ks, and then a line of output for each row, corresponding to the keys
   in ks. If ks are not specified, use the keys of the first item in rows.
   opts:
  `:left-aligned?` if truthy, align the columns left instead of right.
  `:markdown?` if truthy, change the format slightly to make this a markdown table. "
  {:added "1.3"}
  ([ks rows {:keys [left-aligned? markdown?]}]
   (when (seq rows)
     (let [widths (map
                   (fn [k]
                     (apply max (count (str k)) (map #(count (str (get % k))) rows)))
                   ks)
           spacers (map #(apply str (repeat % "-")) widths)
           fmts (map #(str "%" (when left-aligned? "-") % "s") widths)
           fmt-row (fn [leader divider trailer row]
                     (str leader
                          (apply str (interpose divider
                                                (for [[col fmt] (map vector (map #(get row %) ks) fmts)]
                                                  (format fmt (str col)))))
                          trailer))]
       (println)
       (println (fmt-row "| " " | " " |" (zipmap ks ks)))
       (println (fmt-row "|-" (if markdown? "-|-" "-+-") "-|" (zipmap ks spacers)))
       (doseq [row rows]
         (println (fmt-row "| " " | " " |" row))))))
  ([rows opts] (print-table-2 (keys (first rows)) rows opts)))