On Friday, 4 April 2014 at 09:22:16 UTC, Atila Neves wrote:
enum hasAccept(T) = is(typeof(() {
auto s = T();
auto foo = FooVisitor();
s.accept(foo);
auto bar = BarVisitor();
s.accept(bar);
}));
I have lately started to favor separated asserts as opposed to
combined constraints:
mixin template hasAccept(T)
{
static assert (
is(typeof(() { auto s = T(); })),
"Can't create instance of " ~ T.stringof
);
static assert (
is(typeof(FooVisitor)),
"FooVisitor is not defined"
);
// .. and so on
}
It is much less elegant and does not fix issue fundamentally but
speeds up debugging for end user of the library quite a lot.
