On Fri, Apr 24, 2009 at 19:49, Edward Kmett <[email protected]> wrote:
> On Fri, Apr 24, 2009 at 5:11 PM, Denis Bueno <[email protected]> wrote:
>> Is there an Ord instance that can be dynamically changed in this way?
>>
>> My first idea is something like this:
>>
>> data CompareRecord = CR{ rCompare :: Record -> Record -> Ordering,
>> unCR :: Record }
>> instance Ord CompareRecord where
>> compare (CR cmp x) (CR _ y) = cmp x y
>>
>> where the rCompare field would be a function that is based on the
>> flags passed to the command-line problem. But this has an ugly
>> asymmetry. Does anyone have any other ideas?
>
> You can make a safer 'CompareRecord' using 'reflection' from hackage:
This is what I ended up doing and it worked out great. Thanks for the
suggestion.
Denis
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