On 3/6/20 6:51 AM, wjoe wrote:
On Thursday, 5 March 2020 at 18:33:41 UTC, Adam D. Ruppe wrote:
On Thursday, 5 March 2020 at 14:24:33 UTC, wjoe wrote:
[...]
template opDispatch(string name) {
auto opDispatch(T, Args...)(Args args) {
...
}
}
[...]
NOTE: opDispatch suppresses internal compile errors, it will just say
"no such property whatever". you can explicitly instantiate with
`f.opDispatch!"whatever` to help see better errors.
Follow-up question:
Calling f.whatever!SomeResource(...); works no problem.
However I can't figure out how to call a function by explicitly
instantiating opDispatch.
Since f.opDispatch!"load"(handle, "wallpaper.png");
doesn't compile, I refreshed my memory about the shortcut syntax and the
eponymous syntax and the way I read it is that this is a template of a
template.
So I tried this: f.opDispatch!"load".opDispatch!Bitmap(handle,
"path/to/wallpaper.png");
This doesn't work, because an eponymous template does not provide access
to the internals of the template.
But this doesn't compile either and errors out with:
Error: Cannot resolve type for f.opDispatch(T, ARGS...)(ResourceHandle
handle, ARGS args)
I don't understand this error message. Which type can't be resolved?
Is there a way to look at output of what the compiler generates for
f.whatever!SomeResource(...); ?
You can use -vcg-ast, but this isn't necessarily going to be compilable
code.
D doesn't allow chained instantiation (i.e. (A!B)!C), so you need to use
either a mixin or a helper:
import std.meta;
enum fname = "load";
Instantiate!(f.opDispatch!fname, Bitmap)("path/to/wallpaper.png")
or
mixin("f." ~ fname ~ "!(Bitmap)(...);");
I'm assuming fname is given to you as a compile-time string and that's
why you'd need to run opDispatch manually.
-Steve
