Re: Proposal: add an order-reversing newtype to Data.Ord

On 11.07.12 4:31 AM, Conrad Parker wrote:

On 10 July 2012 23:28, Twan van Laarhoven wrote:

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On 10/07/12 14:31, Strake wrote:

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On 09/07/2012, Edward Kmett wrote:

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I would be happy enough with just re-exporting Down and calling it a day. Last time this topic came up it was bikeshedded to death without resolution.

Why is it called "Down"? Is this a mathematical term?

I believe the Down newtype was introduced for use with extended list comprehension, things like [ name u | u<- users, then sort (Down (salary x)) ].

That is illustrative; it reads much better than Reverse or DualOrd would, and I expect that sort is the most common use of an Ord instance.

+1 for re-exporting Down.

+1 for Down. (DualOrd would be also ok, but sounds artifical. Reverse has too much connotation of list-reverse for my taste.) -- Andreas Abel <>< Du bist der geliebte Mensch. Theoretical Computer Science, University of Munich Oettingenstr. 67, D-80538 Munich, GERMANY andreas.abel@ifi.lmu.de http://www2.tcs.ifi.lmu.de/~abel/