On 7/11/17 10:08 AM, jmh530 wrote:
On Tuesday, 11 July 2017 at 07:42:22 UTC, Timon Gehr wrote:
Yes, this code works and does what you want. (The difference to inout
is that you actually get three different implementations and you are
able to vary the implementation based on T.)
Clearly, this has more power than inout.
It's not as good actually. In the mutable form, you can modify the data.
It all depends on if you care about const guarantees or bloat. If you
don't and just want to handle all forms, you can use a template (much
easier IMO than using static foreach).
I suppose what I'm wondering if it makes inout superfluous.
I would say no, inout has a very well defined and convenient mechanism
to deal with properties on all const flavors of objects. There are many
who say templates are good enough, so YMMV. However, nothing so far has
successfully implemented the requirement that during the inout function
execution, the compiler enforces no mutability.
The other major use of inout is something like
class Foo
{
void bar(int t) inout
hm..., this should probably return inout for it to make sense.
{
}
}
which I imagine could be replaced now with SetFunctionAttributes, though
my method was a little ugly and I don't know if there's a more elegant
approach with static foreach.
There is a way to do it with 'this' template parameter:
int * member;
auto bar(this T)()
{
return member; // returns const, immutable, or mutable depending on
modifier for 'this'
}
Still is bloated into multiple instantiations, and still allowed to
mutate for mutable call. Plus it's confusing.
-Steve
