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1.3.0

trampoline

trampoline can be used to convert algorithms requiring mutual
recursion without stack consumption. Calls f with supplied args, if
any. If f returns a fn, calls that fn with no arguments, and
continues to repeat, until the return value is not a fn, then
returns that non-fn value. Note that if you want to return a fn as a
final value, you must wrap it in some data structure and unpack it
after trampoline returns.

1 Example top

link | changes
```
user> (defn foo [x]
        (if (< x 0)
          (println "done")
          #(foo (do (println :x x) (dec x)))))
#'user/foo

;; trampoline will keep calling the function for as long as "foo" returns a function.
user> (trampoline foo 10)
:x 10
:x 9
:x 8
:x 7
:x 6
:x 5
:x 4
:x 3
:x 2
:x 1
:x 0
done
nil
```
user> (defn foo [x] (if (< x 0) (println "done") #(foo (do (println :x x) (dec x))))) #'user/foo ;; trampoline will keep calling the function for as long as "foo" returns a function. user> (trampoline foo 10) :x 10 :x 9 :x 8 :x 7 :x 6 :x 5 :x 4 :x 3 :x 2 :x 1 :x 0 done nil

Source clojure/core.clj:5535 top

(defn trampoline
  "trampoline can be used to convert algorithms requiring mutual
  recursion without stack consumption. Calls f with supplied args, if
  any. If f returns a fn, calls that fn with no arguments, and
  continues to repeat, until the return value is not a fn, then
  returns that non-fn value. Note that if you want to return a fn as a
  final value, you must wrap it in some data structure and unpack it
  after trampoline returns."
  {:added "1.0"
   :static true}
  ([f]
     (let [ret (f)]
       (if (fn? ret)
         (recur ret)
         ret)))
  ([f & args]
     (trampoline #(apply f args))))

Vars in clojure.core/trampoline:

Used in 0 other vars

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Clojure Core

Namespaces

trampoline

clojure.core

1 Example top

See Also top

Source clojure/core.clj:5535 top

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