michael rice wrote on 19.05.2009 18:16:
Cool!
Is there *anything* Haskell *can't* do?
Well, I haven't found a way to emulate polymorphics kinds yet, and I feel like
I need them. Other than than - probably no.
Michael
--- On *Mon, 5/18/09, David Menendez /<[email protected]>/* wrote:
From: David Menendez <[email protected]>
Subject: Re: [Haskell-cafe] showing a user defined type
To: "Ryan Ingram" <[email protected]>
Cc: [email protected]
Date: Monday, May 18, 2009, 10:26 PM
On Mon, May 18, 2009 at 10:02 PM, Ryan Ingram <[email protected]
</mc/[email protected]>> wrote:
> Unfortunately, you can't derive Show on Chain as defined, because it
> contains a function:
Sure you can. I just tried the following, and it compiled without
complaints.
> import Text.Show.Functions
>
> data Chain = Link Int (Int -> Chain) deriving (Show)
The usual warnings about orphan instances apply, but the purpose of
the Text.Show.Functions module is to provide a standard Show instance
for functions so that libraries (e.g., QuickCheck) don't declare
conflicting instances.
--
Dave Menendez <[email protected] </mc/[email protected]>>
<http://www.eyrie.org/~zednenem/ <http://www.eyrie.org/%7Ezednenem/>>
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