Generic tries (long)
Isaac Dupree
isaacdupree at charter.net
Sat Jun 21 09:51:00 EDT 2008
Jamie Brandon wrote:
>> Why not just use
>>
>> class (Ord k, GMap map k) => OrderedGMap map k where
>
> Most of the maps I will be implementing will respect the ordering that
> would be derived by GHC, regardless of the actual Ord instance. There
> is no way, in general, to derive a trie that respects an existing Ord
> instance but I still want to expose the bytewise ordering in the trie.
Well, you could use a newtype for the key, when necessary. But does
that suffer from
1. the risk of accidentally not using a newtype?
2. is it an inconvenience to the users of the map? I can't tell...
Is it a bad idea to require an Ord context even if you don't use it? It
could supply a default method... but would surely confuse people like
(1) above.
-Isaac
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