Proposal: Applicative => Monad: Call for consensus

Henning Thielemann lemming at henning-thielemann.de
Mon Jan 17 01:25:17 CET 2011


On Sun, 16 Jan 2011, wren ng thornton wrote:

> On 1/16/11 12:43 PM, Henning Thielemann wrote:
>> Maciej Piechotka schrieb:
>> 
>>> I agree that there are advantages of both ways and they are perfectly
>>> compatible with each other. While I don't know about GHC internals I'd
>>> assume that class v-tables (term borrowed from C++ I'm not sure about
>>> Haskell terminology) is per-class and not copied for each function
>>> invocation.
>> 
>> "Method dictionary"
>> 
>> http://www.haskell.org/haskellwiki/OOP_vs_type_classes
>
> Perhaps I missed it, but I don't see anything in that page clarifying whether 
> the actual underlying table is shared (i.e., the dictionary is just a pointer 
> to a global table) or not (i.e., the dictionary is a constructed copy of the 
> table). As far as the surface language is concerned the distinction doesn't 
> matter, but as far as people worrying about performance considerations due to 
> the size of dictionaries it does.

Sorry, I just wanted to answer the question how these class v-tables are 
called in Haskell.



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