Open Methods: From C++ to D

[Jean-Louis Leroy via Digitalmars-d-announce]

On Wednesday, 30 August 2017 at 18:20:46 UTC, Jean-Louis Leroy 
wrote:
> On Wednesday, 30 August 2017 at 18:05:38 UTC, jmh530 wrote:
>> On Wednesday, 30 August 2017 at 17:24:55 UTC, Jean-Louis Leroy 
>> wrote:
>>>
>>> We had a discussion about automating the call to 
>>> updateMethods but I don't think that anybody thought of 
>>> putting it in registerMethods. It might work. I'll look into 
>>> it. Thanks for the suggestion...
>>
>> Ali had suggested something similar[1]. I think your concern 
>> was that it would get called multiple times, but shared static 
>> module constructors runs once a program (static module 
>> constructor runs once per thread).
>>
>> [1] http://forum.dlang.org/post/okljj1$ktb$1@digitalmars.com
>
> Ah yes...So the problem is that registerMethods emits static 
> ctors that fill data structures representing the methods and 
> the specializations. They have to run - all of them - before 
> updateMethods. Thus, sadly Q's suggestion won't work.

Yes I remember now...even if we arrange to put the call to 
updateMethods in its own static ctor, coming after all the other 
static ctors, we don't know if there will be more modules with 
more methods afterwards. So we would have to do the updateMethods 
work each time, lest this module is the last. And updateMethods 
is costly: not only does it figure out all the dispatch tables, 
it also calculates a perfect hash (if @mptr is used) using a 
random algorithm.