std.mixins

[Andrei Alexandrescu]

On 8/30/10 20:04 PDT, dsimcha wrote:
> I've been toying for a long time with the idea of a std.mixins for Phobos that
> would contain meta-implementations of commonly needed boilerplate code for
> mixing into classes and and structs.  I've started to prototype it
> (http://dsource.org/projects/scrapple/browser/trunk/std_mixins/std_mixins.d).
>   So far I have a mixin for struct comparisons, which is useful if you need a
> total ordering for use with sorting or binary trees, but don't care exactly
> how that ordering is defined.  I've also got a mixin that converts a class to
> a Singleton, and uses thread-safe but efficient mechanisms to deal with the
> __gshared singleton case.
>
> I'm also thinking of creating some mixins to allow cloning of arbitrarily
> complicated object graphs, provided that you don't stray outside of SafeD.  Is
> this worth implementing or will it likely be solved in some other way at some
> point?
>
> Right now I'd just like to milk the D community for ideas.  What other pieces
> of boilerplate code do you find yourself writing often that the standard
> library should help with?

Sounds like a good idea, but I think the name is not too descriptive as 
it refers to mechanism. We shouldn't have std.classes or std.structs in 
there, should we? :o) Therefore std.mixins sounds like an awkward way to 
group together pieces of functionality that may be very diverse.

FWIW I think you don't need any mixins to implement cloning. But I do 
encourage you to work on cloning - I wanted for the longest time and 
couldn't get to it. A cloning routine would need to keep a map of 
pointer to pointer to make sure in only clones each object in a graph once.


Andrei