[Haskell-cafe] Re: Re[2]: Tuple-like constructors

Brian Hulley brianh at metamilk.com
Wed Feb 8 16:17:27 EST 2006


Robert Dockins wrote:
> [Moved to cafe; time to stop bothering the Haskell' committee...]
>
> On Feb 8, 2006, at 1:19 PM, Malcolm Wallace wrote:
>> Robert Dockins <robdockins at fastmail.fm> writes:
>>
>>> instance (Bin a,Bin b,Bin c,Bin d) => Bin (a,b,c,d)
>>>
>>> See the problem?  Sooner or later (probably sooner) I'll get tired
>>> of typing.  I have to write down an 'instance' declaration for each
>>> value of n.  Clearly this can't generalize to all n.

Wouldn't it be nice to have dependent types? (I'm also thinking of all the 
numerical algorithms that could benefit from such an extension, but I don't 
know what syntax one could use)

Regards, Brian. 



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