Andrei Alexandrescu wrote:
Shin Fujishiro wrote:
Hi,
I've had fun with the allMembers traits over the past few days and found
it more powerful than I thought.
__traits(allMembers, T) returns the member names of T. As some might
already know, T is not restricted to a class or struct; it can also be
an enum, template, or even module. Try this:
--------------------
enum E { a, b, c }
template T() { int x, y, z; }
import std.stdio;
pragma(msg, __traits(allMembers, E).stringof);
pragma(msg, __traits(allMembers, T).stringof);
pragma(msg, __traits(allMembers, std.stdio).stringof);
--------------------
You'll like the result :). It must be usable!
For example, using allMembers with enums, I could implement
enumToString and enumFromString without defineEnum.
Code: http://codepad.org/HVvPjoI7
So, what other uses could there be?
Wow, I didn't know about this! It might as well be everything needed for
a full-blown compile-time reflection package!
To answer your question: for starters, try to implement BlackHole and
WhiteHole as explained here:
http://erdani.dreamhosters.com/cranking-policies-up.pdf
First of all, congratulations for conjuring up a cool (and
marketing-savvy name) for a concept!!!
Suppose I decide to use BlackHole as a base class. Would that mean that
I create the base class like
class RichardNixon createBlackHoleClass!()
class DerivedRN : RichardNixon {
/* something declared here, makes no difference in this example */
int foo(int ip) {/* whatever */}
}
and then, I'd expect it to work like
void main() {
DerivedRN drn = new DerivedRN;
float ivar, jvar;
jvar = drn.bar(ivar); // note: bar, not foo
}
and it'd work like RichardNixon were actually defined as
class RichardNixon {
float bar(float jv) { return float 0; } // or whatever
}
