On Wednesday, May 17, 2017 at 3:57:44 PM UTC+1, Rupert Smith wrote:
>
> On Wednesday, May 17, 2017 at 11:40:35 AM UTC+1, Rupert Smith wrote:
>>
>> http://package.elm-lang.org/packages/TSFoster/elm-heap/latest
>>
>
> Bugger. This heap implementation does not allow and arbitrary comparison
> function. It has this:
>
> by : (a -> comparable) -> Options b -> Options a
>
> But that requires a mapping from the type being compares onto comparable.
>
> If there is an implementation that lets me use a comparison function of
> type 'a -> a -> Order', that would be better.
>
But internally it does use an 'a -> a -> Order':
type Options a
= Options
{ order : SortOrder
, compare : a -> a -> Order
}
Which it builds by converting an 'a -> comparable' function:
makeCompare : (a -> comparable) -> (a -> a -> Order)
makeCompare fn a b =
Basics.compare (fn a) (fn b)
Perhaps the author meant to expose Options(..) so users can build their own
compare function?
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