On Monday, 4 February 2013 at 07:15:47 UTC, Maxim Fomin wrote:
Strictly speaking they are not illegal, they just do not have
context pointer which points to enclosing struct. Thus, even if
you manage to return outer struct data from inner, this would
not work if nested struct is created alone, without outer
struct.
I'm aware of that. With nested structs we know they will be part
of a larger structure so making & using them outside of their
parent struct just doesn't work; At best you can move them as
storage but couldn't instantiate them yourself.
Thoughts and ideas?
I do not think there are problems with how nested structs with
context pointer should be defined. I consider implementation to
be a serious problem since we often have <100 messages in forum
and no practice steps.
What I expect to be a problem is storing pointer to outer
struct in nested struct. The problem is that most structs are
stack allocated and stack pointer can be invalidated. Example
http://d.puremagic.com/issues/show_bug.cgi?id=9352
Yes I know, this is why returning a struct beyond it's level or
where it may be invalidated wouldn't be allowed, which combats
this (or even removes it altogether). But as much as I think on
the matter of nested structs, I keep coming back to that they are
an implementation detail of the parent structs and not really
intended to leave them.
