Catch upsets semantic approximation?

Question

The order of semantic approximation states that if a function is fdefined when its arguments are absent, then it fis a constant in this argument (it does not use it). But consider this function,

import Control.Exception

handleAll :: SomeException -> IO ()
handleAll e = putStrLn "caught"

f :: String -> IO ()
f x = catch (putStrLn x) handleAll

f undefineddisplays caughtin GHCi, so it looks specific. However, fit is not a constant in its argument, because it f "test"displays test.

Is there a mistake somewhere?

Answer 1

catch , ( ). . (pdf) , GHC.

, " " Haskell, IO a ( ).

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data IO a = MkIO

catch

catch a h = MkIO

f, f undefined f "test" MkIO.

[[IO t]] = {⊥ < ⊤}

, IO, seq IO, , , length :: [Bool] -> Integer, , , -. , , .