RFC: Can DefaultSignature compile-time conditional APIs be regarded "benign"?

Henning Thielemann lemming at henning-thielemann.de
Mon Nov 12 10:58:58 CET 2012

On Mon, 12 Nov 2012, Bas van Dijk wrote:

> I like those ideas.
> However this still leaves #7395 unresolved.
> I do like hvr's idea of using the deriving mechanism to derive classes
> with DefaultSignatures.

The more I think about it the more my impression becomes that we are 
trying to solve a problem the complicated way where a simple solution 
already exists. I see the motivation behind DefaultSignatures and 
encountered the situation often enough that lead to the introduction of 
DefaultSignatures. However I always solved the problem by providing 
functions like genericSize or genericRnf (though I have not used Generics 
for default implementations). Its simple and its portable. Now with 
DefaultSignatures we can simplify some bits, but in order to stay portable 
with DefaultSignatures things get more complicated than staying portable 
without DefaultSignatures at all.

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