How can I get this UDA at compile time?
Jack
jckj33 at gmail.com
Sun Feb 21 06:12:50 UTC 2021
I've had a struct like this:
struct Attr
{
string value;
}
struct Foo
{
@(Attr("a attr"))
enum a = Foo(10);
@(Attr("b attr"))
enum b = Foo(11);
int x;
int y;
bool doY = true;
int value()
{
return x;
}
}
I'd like to get that atrribute's value at compile time, something
like this:
enum s = Foo.a.baa;
enum s2 = Foo.b.baa;
writeln(s); // a attr
writeln(s2); // b attr
I did this:
string baa()
{
import std.traits : getUDAs, hasUDA;
static foreach(field; __traits(allMembers, Foo))
{{
alias m = __traits(getMember, Foo, field);
static if(is(typeof(m) == Foo))
{
if(m.value == this.value)
return getUDAs!(m, Attr)[0].value;
}
}}
return null;
}
that was working fine, but I needed to switch value property from
Foo struct, so that I can't read this value at CTFE anymore, so
this fails now:
if(m.value == this.value)
return getUDAs!(m, Attr)[0].value;
How can I solve this?
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