On 21/07/06, Dusan Kolar wrote:

Prelude> putStr "Ahoj\n" Ahoj Prelude> putStr "Ahoj\n" `seq` 3+3 6 Prelude> :q Leaving GHCi.

And not

Prelude> putStr "Ahoj\n" Ahoj Prelude> putStr "Ahoj\n" `seq` 3+3 Ahoj 6

Well, I understand that seq evaluates the first argument. But the result of evaluating putStr is a monadic action. Not execution of that action. Regards, Piotr Kalinowski -- Intelligence is like a river: the deeper it is, the less noise it makes

Hello Dusan, The reason why that does not work as you expect it to is because the type of the whole expression is not monadic. Therefore it will basically evaluate the action until it's an action ready to be executed, but not execute it, cause it's not in the IO monad. It's the same as having a list of [putStr "a", putStr "b"]. Until you start placing these actions in the IO monad, they'll just be values. Hope that's somewhat clear Dusan Kolar wrote:

Hello all,

my question is probably dull. So answers to better investigate manual are welcome. Why is this correct?

___ ___ _ / _ \ /\ /\/ __(_) / /_\// /_/ / / | | GHC Interactive, version 6.4.1, for Haskell 98. / /_\\/ __ / /___| | http://www.haskell.org/ghc/ \____/\/ /_/\____/|_| Type :? for help.

Loading package base-1.0 ... linking ... done. Prelude> putStr "Ahoj\n" Ahoj Prelude> putStr "Ahoj\n" `seq` 3+3 6 Prelude> :q Leaving GHCi.

And not

Prelude> putStr "Ahoj\n" Ahoj Prelude> putStr "Ahoj\n" `seq` 3+3 Ahoj 6

???

Does it have something common with monads or is it a behavior of seq?

Thanks,

Dusan

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