On Tuesday, 15 April 2014 at 21:42:51 UTC, Walter Bright wrote:
On 4/15/2014 2:41 PM, Brad Anderson wrote:
Yes, please. Too few of the attributes have inverse attributes.
That's a subject for another DIP.
This would go fairly well with Andrei's idea of passing true or
false to an attribute to enable or disable it.
@gc(false) void fun() {}
Also, as was mentioned earlier in the thread, if @gc was actually
implemented as a UDA just like any other, gc could simply be a
struct that the compiler looks for, something along those lines.
struct gc
{
bool enable;
//...
}
Which naturally implements Andrei's proposed syntax. The same
could be done for @property, @safe, etc. If we had DMD as a
library, @gc probably wouldn't even need to be "special", i.e.,
compiler magic.
Finally, as MonarchDodra mentioned, the number of optional
attributes to mark a function with can get to be a problem after
awhile. I have two ideas on this. One is extending the concept of
aliases to also alias attributes, like so:
//TypeTuple or just bare list?
alias everything = TypeTuple!(@safe, nothrow, pure, @gc(false));
or
alias everything(Attrs...) = Attrs;
I think that the Microsoft language with effect algebra
(Bearophile has mentioned it before) does this. E.g., pure is
actually:
alias pure: noeffects nothrow //... (I don't remember the actual
syntax)
Secondly, this could just be a "higher level attribute". I don't
know if this would require a language change or not...
struct Everything
{
bool _pure;
bool _nothrow;
//...
}
