[Haskell-cafe] Defining methods generically for a class
jefferson.r.heard at gmail.com
Thu Jan 8 12:28:14 EST 2009
That's probably the best thing to do, yes. The purpose of doing so
was for Data.List.delete, but I see now there's a Data.List.deleteBy,
so I can use the regionEquals function as my equality predicate.
On Thu, Jan 8, 2009 at 12:26 PM, Martijn van Steenbergen
<martijn at van.steenbergen.nl> wrote:
> Hi Jeff,
> Jeff Heard wrote:
>> instance Region a => Eq a where
>> regiona == regionb = all $ zipWith (==) (bounds regiona) (bounds
> If you want to be Haskell98 compliant, why not define regionEquals :: Region
> a => a -> a -> Bool as above and use that everywhere instead of (==)?
> If you insist on using the overloaded (==), then in Haskell98 you will need
> to define individual Eq instances for all your custom region types. However,
> you can simply define (==) = regionEquals for all those types.
> Hope this helps,
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