On Monday, 10 December 2012 at 07:48:37 UTC, Ali Çehreli wrote:
On 12/09/2012 10:43 PM, js.mdnq wrote:
> I thought `alias this` essentially treats the object as the
alias.
>
> struct A {
> alias value this;
> int value;
> void func();
> }
>
> A a;
>
> then a is essentially the same as a.value?
No. 'alias value this' means "when this object is used in a
context where the type of 'value' is expected, then use the
'value' member instead."
In your example above, it means "when A is used in place of
int, use 'value' instead." It is basically for automatic type
conversion.
(A reminder: Although the language spec allows multiple alias
this declarations, current dmd supports only one.)
> a.func() would be
> a.value.func() which makes no sense?
a.func() would still call A.func on object 'a' because 'a' is
an A. Only when 'a' is used as an int, 'value' is considered.
> At least that is how I thought
> alias this worked? (it's obviously more complex than what I
thought)
Perhaps it is simpler than what you thought. :)
> (I'm new to D so you'll have to forgive all the stupid
questions ;)
Your questions make all of us learn more. :)
> D seems quite powerful and many useful ways to do things but
I still
> haven't wrapped my head around all the intricacies)
Indeed... There are a lot of features.
Ali
Yeah, basically it's close to what I was thinking but I guess the
opGet, which I'm still not familiar with, behaves a bit different
when aliased. Possibly because we are aliasing a operator(or
method?) which is different than aliasing a type?
e.g., `alias opAssign this;` makes no sense to me ;/
Thanks for the help...
