Aggregates & associations

[Jarrett Billingsley]

"Bruce Adams" <tortoise_74 at yeah.who.co.uk> wrote in message 
news:op.t3mssesyxikks4 at lionheart.cybernetics...

> Sorry I should have qualified that. Scope as I understand it, declares 
> whether
> a variable should be deleted or it. i.e. whether it is owned by the 
> current scope,
> which in the proposed extension would mean class scope. It does not say 
> anything
> about the memory layout. Whether the object is a value or reference is 
> still up
> for grabs. It doesn't usually matter in functions but in a class it does, 
> at least
> as an optimisation.

See, it's an optimization.  Guess who should be doing optimizations?  Hint: 
it's not the programmer.  I'd place manual specification of whether a scope 
class is allocated inline the body of its owning class or function in the 
same category as "inline" and "register" -- ultimately meaningless hints to 
the compiler to do something that it can figure out better than you can. 
Chances are if we got scope class references in classes they _would_ be 
inlined into the owning class's body, if for no other reason than the 
principle of least surprise -- it already happens in functions -- and also 
because, well, it's a good optimization.

This is why C++ is complex.  It gives you all these possibilities and 
features, but leaves it up to you to make something useful out of them.  D 
tries to give you useful _semantic_ features whose semantics leave room for 
optimization, freeing you from dealing with the low-level crap that C++ 
makes you deal with.  I don't want D to go to the way C++ does it.