cond->>

macro

since v0.0-1798

imported clojure.core/cond->>

Edit

Details:

Examples:

(def filter? true)
(def sum? true)

(cond->> [1 2 3 4]
  filter? (filter even?)
  sum?    (reduce +))
;;=> 6

See Also:

• ->
• ->>
• cond->
• cond

Takes an expression and a set of test/form pairs. Threads expr (via ->>)
through each form for which the corresponding test expression
is true.  Note that, unlike cond branching, cond->> threading does not short circuit
after the first true test expression.

(defmacro cond->>
  {:added "1.5"}
  [expr & clauses]
  (assert (even? (count clauses)))
  (let [g (gensym)
        steps (map (fn [[test step]] `(if ~test (->> ~g ~step) ~g))
                   (partition 2 clauses))]
    `(let [~g ~expr
           ~@(interleave (repeat g) (butlast steps))]
       ~(if (empty? steps)
          g
          (last steps)))))