1.0 KiB
1.0 KiB
Debug
Stubbing
undefined
undefined :: a
An undefined expression standing in for an incomplete program, unevaluated type witness, or unreachable code branch.
Example:
> import Foreign.Storable
> print (sizeOf (undefined :: Int))
8
notImplemented
notImplemented :: a
An undefined expression standing in for a yet to completed program.
Example:
main :: IO ()
main = notImplemented
Tracing
trace
trace :: Print b => b -> a -> a
Example:
traceM
traceM :: (Monad m) => Text -> m ()
Example:
traceId
traceId :: Text -> Text
Example:
traceShowM
traceShowM :: (P.Show a, Monad m) => a -> m ()
Example:
traceShowId
traceShowId :: P.Show a => a -> a
Example:
traceShow
traceShow :: P.Show a => a -> b -> b
Example:
traceIO
traceIO :: Print b => b -> a -> IO a
Example: