idris-1.2.0: test/basic022/basic022.idr

import Data.IORef

count : HasReference ffi =>  Nat -> IORef Integer -> IO' ffi ()
count Z ref
    = do x <- readIORef' ref
         printLn' x
count (S k) ref
    = do modifyIORef' ref (+1)
         count k ref

main : JS_IO ()
main = do r <- newIORef' 0
          count 1000 r