luciano/xforms
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

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

Browse source
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
Show stats Download patch file Download diff file Expand all files Collapse all files

17
src/net/cgrand/xforms.clj
View file

@ -433,12 +433,17 @@
(vswap! vwacc f x))
acc))))))))
(defn count [rf]
(let [n (java.util.concurrent.atomic.AtomicLong.)]
(fn
([] (rf))
([acc] (rf (unreduced (rf acc (.get n)))))
([acc _] (.incrementAndGet n) acc))))
(defn count
"Count the number of items. Either used directly as a transducer or invoked with two args
as a transducing context."
([rf]
(let [n (java.util.concurrent.atomic.AtomicLong.)]
(fn
([] (rf))
([acc] (rf (unreduced (rf acc (.get n)))))
([acc _] (.incrementAndGet n) acc))))
([xform coll]
(transduce (comp xform count) rf/last coll)))
(defn multiplex
"Returns a transducer that runs several transducers (sepcified by xforms) in parallel.