Data.Fixed.Fixed constructor

Ashley Yakeley ashley at semantic.org
Fri Jul 24 02:13:26 EDT 2009


On Fri, 2009-07-24 at 02:03 -0400, David Menendez wrote:
> If the constructor is already exposed, then you don't lose abstraction
> with a derived instance.
> 
> Out of curiosity, what made you decide to expose the constructor?

As a general rule, if there is a correct Data instance, then it is
always possible to recreate the constructors. Since I am providing a
Data instance, I might as well provide the MkFixed constructor.

Consider: your Data instance is StringRep-based. My automatically
derived one is Integer-based. Both suggest concrete representations, but
the Integer one makes much more sense to me. And as it happens, that's
the actual concrete representation.

-- 
Ashley Yakeley




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