[Haskell-cafe] Re: Type classes

20 Mar 2006


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"Geest," == Geest, G van den  writes:
Geest,> I suppose you want to define compareEntries like this:
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compareEntries (Entry x) (Entry y) = compareEntries x y
Geest,> An option is to just implement it the following way
Geest,> (Haskell98!):
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class DatabaseEntry e where entryLabel :: e -> String formatEntry
:: e -> String compareEntries :: e -> e -> Ordering
data Entry a = Entry a
No. I don't want that. The database parsing function returns
Map.Map String Entry but entries can of different types (and
these type vary over styles).

-- 
WBR,
Max Vasin.