On Sunday, 3 May 2015 at 17:48:55 UTC, ketmar wrote:
On Sun, 03 May 2015 17:21:58 +0000, filcuc wrote:
Hi all,
i'm working in the generation of the code but i'm failing in
extracting
a function return type when invoking the ReturnType!(T) type
trait and
mixing it with __traits(getMember) function.
Can anyone help me? or explaining what is happenning?
i've created a gist here:
https://gist.github.com/filcuc/14c3a6cac89beb69cccd
The error message is the following:
main.d-mixin-58(58): Error: template instance
main.Person.ReturnType!(name) does not match template
declaration
ReturnType(func...) if (func.length == 1 && isCallable!func)
main.d-mixin-58(58): Error: template instance
std.traits.ReturnType!(Monitor) does not match template
declaration
ReturnType(func...) if (func.length == 1 && isCallable!func)
main.d(73): Error: template instance main.IterateUDA!(Person)
error
instantiating
the thing is that you mixed CTFE and runtime code in a weird
way. ;-)
the following works:
void IterateUDA(T)() {
import std.typetuple : staticIndexOf;
foreach (member; __traits(allMembers, T)) {
// Check that the given member is a function
static if (is(typeof(__traits(getMember, T, member)))) {
bool isFunction = __traits(isVirtualFunction,
__traits(getMember,
T, member));
if (!isFunction) continue;
// Retrieve the UDA
enum attributes = __traits(getAttributes,
__traits(getMember, T,
member));
// Extract the Function Return Type and Arguments if
`Slot()` is
found
static if (staticIndexOf!(Slot(), attributes) >= 0) {
enum returnType = ReturnType!(__traits(getMember, T,
member)).stringof;
import std.stdio;
writeln(returnType);
}
}
}
}
yet i think you need to read more about CTFE and
metaprogramming, to
avoid mixing different code.
Yep sorry,
i'm still learning :)
However thank you all for your help and the quick answer.
As you suggested wrapping the body with the static if solved the
problem.
I've updated the gist
https://gist.github.com/filcuc/14c3a6cac89beb69cccd
Thanks!
