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x/count can now be used as a transducing context (x/count xform coll). /cc @iig

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This commit is contained in:
Christophe Grand 2016-12-08 12:01:49 +01:00
parent 62c3dd15cc
commit d16bd380fa
1 changed files with 11 additions and 6 deletions
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17
src/net/cgrand/xforms.clj
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@ -433,12 +433,17 @@
(vswap! vwacc f x)) (vswap! vwacc f x))
acc)))))))) acc))))))))
(defn count [rf] (defn count
(let [n (java.util.concurrent.atomic.AtomicLong.)] "Count the number of items. Either used directly as a transducer or invoked with two args
(fn as a transducing context."
([] (rf)) ([rf]
([acc] (rf (unreduced (rf acc (.get n))))) (let [n (java.util.concurrent.atomic.AtomicLong.)]
([acc _] (.incrementAndGet n) acc)))) (fn
([] (rf))
([acc] (rf (unreduced (rf acc (.get n)))))
([acc _] (.incrementAndGet n) acc))))
([xform coll]
(transduce (comp xform count) rf/last coll)))
(defn multiplex (defn multiplex
"Returns a transducer that runs several transducers (sepcified by xforms) in parallel. "Returns a transducer that runs several transducers (sepcified by xforms) in parallel.