Util/Monad.hs

   1 module Util.Monad where
   2 import Control.Monad (foldM)
   3 import Data.Map (Map)
   4 import qualified Data.Map as Map
   5
   6 infixl 1 >>=*
   7 (>>=*) :: Monad m => a -> [a -> m a] -> m a
   8 (>>=*) = foldM $ flip id
   9
  10 buildMap :: (Ord a, Monad m) => [a] -> (a -> m b) -> m (Map a b)
  11 buildMap xs f = Map.empty >>=* (flip map xs $ \x m -> do
  12   y <- f x
  13   return $ Map.insert x y m)
  14