foo.idr

%foreign "scheme:chez,real-time"
         "scheme:racket,current-milliseconds"
time' : PrimIO Int

getTime : IO Int
getTime = primIO time'

export
foo : IO Int -- records time properly, roughly 2 seconds of work
foo = do
  t1 <- getTime
  pure $ foldl (+) (the Int 0) [1..10000000]
  t2 <- getTime
  pure (t2-t1)

foo2helper : IO a -> IO Int
foo2helper act = do
    t1 <- getTime
    act
    t2 <- getTime
    pure (t2-t1)

foo2 : IO Int -- records time wrongly, records 0-1 milliseconds of work
foo2 = foo2helper (pure $ foldl (+) (the Int 0) [1..10000000])