On Wednesday, 17 June 2020 at 16:01:29 UTC, Paul Backus wrote:
On Tuesday, 16 June 2020 at 13:31:49 UTC, Atila Neves wrote:
<snip>
With a few changes, yes (added missing semicolons, changed
IGeometry to Geometry in `measure`, passed the current module
so tardy can find the UFCS functions, added `@safe pure` to
the UFCS functions:
[...]
void main() {
auto r = Rect(3.0, 4.0);
auto c = Circle(5.0);
Geometry.create!__MODULE__(r).measure;
Geometry.create!__MODULE__(c).measure;
}
IMO this can be done more elegantly by separating out the code
that looks up methods in the current module from the code that
does the actual type erasure.
A while ago, I collaborated briefly with Adam Kowalski from the
Dlang discord server on some code to emulate C++-style
argument-dependent lookup in D. Using that code, your example
above would be written:
Geometry.create(r.extended).measure;
Geometry.create(c.extended).measure;
Interesting.
The issue I see here is you might not be able to control which
module has the extension methods. I guess you could alias them in
the module you want to use but that seems clumsy.
In any case, this is trivial:
template extended(string mod = __MODULE__) {
auto extended(A...)(auto ref A args) {
return create!mod(args);
}
}
