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.
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