[Haskell-cafe] looking for examples of non-full Functional Dependencies

Bulat Ziganshin bulat.ziganshin at gmail.com
Wed Apr 16 11:17:14 EDT 2008


Hello Martin,

Wednesday, April 16, 2008, 7:06:07 PM, you wrote:

i'm not 100% sure that you'll find there appropriate examples but i
suggest you too look into http://haskell.org/haskellwiki/Library/Streams
where i've used very sophisticated (for me) FDs

> We're also looking for (practical) examples of "multi-range" functional
> dependencies

class C a b c | c ->> a b

> Notice that there are multiple (two) parameters in the range of the FD.

> It's tempting to convert the above to

class C a b c | c ->> a, c -> b

> but this yields a weaker (in terms of type improvement) system.

> Thanks,
>      Martin



> Tom Schrijvers wrote:
>> Hello,
>>
>> I'm looking for practical examples of non-full functional dependencies 
>> and would be grateful if anyone could show me some or point to 
>> applications using them.
>>
>> A non-full functional dependency is one involves only part of the 
>> parameters of a type class. E.g.
>>
>>     class C a b c | a -> b
>>
>> has a non-full functional dependency a -> b which does not involve c.
>>
>> Thanks,
>>
>> Tom
>>
>> -- 
>> Tom Schrijvers
>>
>> Department of Computer Science
>> K.U. Leuven
>> Celestijnenlaan 200A
>> B-3001 Heverlee
>> Belgium
>>
>> tel: +32 16 327544
>> e-mail: tom.schrijvers at cs.kuleuven.be
>> url: http://www.cs.kuleuven.be/~toms/
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-- 
Best regards,
 Bulat                            mailto:Bulat.Ziganshin at gmail.com



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