On Friday, 6 March 2020 at 13:55:25 UTC, Steven Schveighoffer
wrote:
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
I tried Instantiate this morning after I found a reply you made
to someone else who was trying to chain instantiate. But for the
reason you stated it didn't work.
Funny you mention: mixin("f." ~ fname ~ "!(Bitmap)(...);");
Because that's like my initial implementation :)
As for the the command line switch. My plan wasn't to copy paste.
Sometimes I have a hard time to comprehend results because it's
like I've put water, flour and eggs on the table. Then I'm
presented with a loaf of bread and I'm baffled. Then I want to
understand what happened between putting the ingredients on the
table and the ready baked loaf.
Anyways, thanks for your answers.
