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Today's Topics:
1. Re: Showing Types (Alex Rozenshteyn)
2. Re: Showing Types (Alex Rozenshteyn)
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Message: 1
Date: Tue, 8 Mar 2016 10:09:21 -0500
From: Alex Rozenshteyn <[email protected]>
To: The Haskell-Beginners Mailing List - Discussion of primarily
beginner-level topics related to Haskell <[email protected]>
Subject: Re: [Haskell-beginners] Showing Types
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<CALm==BUBwH0=edr1zz01nobws-b-btsex9src6dnde9ngab...@mail.gmail.com>
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> But it works on concrete types, not functions.
Isn't the problem type variables, not functions?
Prelude Data.Typeable> :set -XScopedTypeVariables
Prelude Data.Typeable> let fun x = case x of {Just (i::Int) -> i + 1;
Nothing -> 0}
Prelude Data.Typeable> :t fun
fun :: Maybe Int -> Int
Prelude Data.Typeable> typeOf fun
Maybe Int -> Int
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Message: 2
Date: Tue, 8 Mar 2016 10:26:21 -0500
From: Alex Rozenshteyn <[email protected]>
To: The Haskell-Beginners Mailing List - Discussion of primarily
beginner-level topics related to Haskell <[email protected]>
Subject: Re: [Haskell-beginners] Showing Types
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<CALm==BWHyVZCZKj2QXOATmvSTxPWT1z9JsZAKiVuD=_waat...@mail.gmail.com>
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And you also run into trouble with typeOf Nothing.
On Tue, Mar 8, 2016 at 10:09 AM, Alex Rozenshteyn <[email protected]>
wrote:
> > But it works on concrete types, not functions.
>
> Isn't the problem type variables, not functions?
>
> Prelude Data.Typeable> :set -XScopedTypeVariables
> Prelude Data.Typeable> let fun x = case x of {Just (i::Int) -> i + 1;
> Nothing -> 0}
> Prelude Data.Typeable> :t fun
> fun :: Maybe Int -> Int
> Prelude Data.Typeable> typeOf fun
> Maybe Int -> Int
>
>
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