On Saturday, 10 February 2018 at 01:01:39 UTC, Ali Çehreli wrote:
On 02/09/2018 03:45 PM, Alex wrote:
> A question about Typedef usage:
> Say, I have the following circumstances
>
> /// --- code --- ///
>
> import std.typecons;
>
> void main()
> {
> MyEA ea;
> MyEB eb;
> ea.tarr.length = 5;
> static assert(!is(MyEA == MyEB));
> static assert(!is(MyEA == E));
> static assert(!is(MyEB == E));
> assert(ea.tarr.length == eb.tarr.length); // line 11
> assert(ea.tarr.length != eb.tarr.length); // line 12
You must have meant
assert(ea.tarr.ptr != eb.tarr.ptr); // line 12
Indeed, .ptr are unexpectedly the same.
Yes... this is a more precise comparison :)
> }
>
> struct T
> {
> size_t i;
> }
>
> struct E
> {
> size_t i;
> static T[] tarr;
To save time to others, note that 'tarr' is a static member
that ends up being shared by two Typedef instantiations.
Yup. They are shared by two Typedef instantiations with different
cookies.
So...
The question is two-fold:
Would it help to alter the init value of the Typedef?
If yes, how to alter it?
If no, is this a bug?
> }
>
> alias MyEA = Typedef!(E, E.init, "A"); // line 26
> alias MyEB = Typedef!(E, E.init, "B"); // line 27
>
> /// --- code ends --- ///
>
> Line 12 yields an assertion error, while line 11 does not.
> This tells me, that despite the fact the types MyEA and MyEB
are
> different they still share the static array, which would
contradict the
> definition of static.
>
> I suppose, the tricky thing is to tweak the init property of
the
> typedefs in lines 26/27 to avoid this clash. How to manage
this?
Ali
