% arg

syntax

since v0.0-1853

in clojure

Edit

Examples:

(map #(* 2 %) [1 2 3])
;;=> (2 4 6)

(def f #(println %1 %2 %&))
(f 1 2 3 4 5)
;; prints: 1 2 (3 4 5)

See Also:

• #() function

(defn- read-arg
  [rdr pct opts pending-forms]
  (if-not (thread-bound? #'arg-env)
    (read-symbol rdr pct)
    (let [ch (peek-char rdr)]
      (cond
       (or (whitespace? ch)
           (macro-terminating? ch)
           (nil? ch))
       (register-arg 1)

       (identical? ch \&)
       (do (read-char rdr)
           (register-arg -1))

       :else
       (let [n (read* rdr true nil opts pending-forms)]
         (if-not (integer? n)
           (throw (IllegalStateException. "Arg literal must be %, %& or %integer"))
           (register-arg n)))))))

(defn- macros [ch]
  (case ch
    \" read-string*
    \: read-keyword
    \; read-comment
    \' (wrapping-reader 'quote)
    \@ (wrapping-reader 'clojure.core/deref)
    \^ read-meta
    \` read-syntax-quote ;;(wrapping-reader 'syntax-quote)
    \~ read-unquote
    \( read-list
    \) read-unmatched-delimiter
    \[ read-vector
    \] read-unmatched-delimiter
    \{ read-map
    \} read-unmatched-delimiter
    \\ read-char*
    \% read-arg
    \# read-dispatch
    nil))