[Haskell-cafe] Inheritance and Wrappers

Henning Thielemann lemming at henning-thielemann.de
Mon Jan 31 21:39:03 CET 2011

On Mon, 31 Jan 2011, Brandon S Allbery KF8NH wrote:

> On 1/31/11 15:24 , Daniel Fischer wrote:
>> want. You could then also enable OverlappingInstances, which would allow
>> you to write other instances, but that extension is widely regarded as
>> dangerous (have to confess, I forgot what the dangers were, one was that
>> instance selection doesn't always do what you want/expect).
> Instance selection will still not look at the context, so multiple instances
> would complain about needing IncoherentInstances, and if you add *that* then
> it does something like taking the first matching instance it finds (again,
> ignoring the context completely).

Since the original poster classified himself as new to Haskell, I'm afraid 
that advanced and dangerous extensions are not the appropriate answer.

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