added some snippet

1 files changed, 16 insertions, 1 deletions

diff --git a/snip/snip.hs b/snip/snip.hs
index 4b7b461..cf2db1f 100644
--- a/snip/snip.hs
+++ b/snip/snip.hs
@@ -1,8 +1,16 @@
 import Control.Monad.Writer 
 import Control.Monad.State
 
+import Data.Tuple.Extra (dupe,first,second)
+import System.Environment (getArgs)
+import Control.Parallel.Strategies (parMap,rseq,rdeepseq)
+
+main = do
+        mainMonTra
+        mainParMap
+
 -- monad transformers in action
-main = print $ 
+mainMonTra = print $ 
        runState (
                runWriterT  (
                    get >>= \a -> 
@@ -12,3 +20,10 @@ main = print $
                    tell [show a]
                    )
                ) 5
+
+-- parallel Map arguments: sparks maps
+mainParMap = do 
+          (sparks:max:_) <- fmap (map read) getArgs
+          let ranges = uncurry zip . second tail . dupe $ [0,(max`div`sparks)..max]
+          let sums   = parMap rdeepseq (\(a,b)->sum [a+1..b]) ranges
+          print $ show (sum sums::Integer)