Is there a way to use Object.factory with templated classes? Or some way to construct templated classes given RTTI of an instance?

[Adam D. Ruppe]

On Thursday, 27 September 2018 at 05:04:09 UTC, Chad Joan wrote:
> The tree nodes are potentially very diverse, but the tree 
> structure itself will be very homogeneous.

The virtual method can still handle that case!

But, if your child array of expressions is already accessible 
through the base interface, I think now your code is going to 
look something more like:

Expression copy(Expression e) {
    // I kinda hate the cast, but create is too generic lol
    // and we already know so it ok here
    Expression n = cast(Expression) typeid(e).create();

    foreach(child; e.children)
       n.children ~= copy(child);

    return n;
}

that's not too bad :)


> I'm having trouble looking this up.  Could you link me to the 
> docs for this?

Well, the create method is actually better anyway (and actually 
documented! I just forgot about it in that first post) but you 
can see more of the guts here 
http://dpldocs.info/experimental-docs/object.TypeInfo_Class.html


> As above, I think this might be a very clean and effective 
> solution for a different class of use-cases :)  I'll keep it in 
> mind though.

Yeah. And I did make one mistake: the tupleof assignment trick 
wouldn't work well for references, so lol it isn't much of a deep 
copy. You'd want to deep copy any arrays too probably.

But sounds like you are already doing that, yay.