On Sun, 14 Aug 2011 01:15:29 +0200, mimocrocodil <[email protected]>
wrote:
Hi!
I am want to extend available enum to provide more items to them.
How I can do this job without manual copying of exsisting enum items?
If what you want is a new enum that contains the values of an existing
enum,
with some additions, this code will do it:
string EnumDefAsString(T)() if (is(T == enum)) {
string result = "";
foreach (e; __traits(allMembers, T)) {
result ~= e ~ " = T." ~ e ~ ",";
}
return result;
}
template ExtendEnum(T, string s) if (is(T == enum) &&
is(typeof({mixin("enum a{"~s~"}");}))) {
mixin("enum ExtendEnum {" ~
EnumDefAsString!T() ~ s ~
"}");
}
unittest {
enum bar {
a = 1,
b = 7,
c = 19
}
import std.typetuple;
alias ExtendEnum!(bar, q{ // Usage example here.
d = 25
}) bar2;
foreach (i, e; __traits(allMembers, bar2)) {
static assert( e == TypeTuple!("a", "b", "c", "d")[i] );
}
assert( bar2.a == bar.a );
assert( bar2.b == bar.b );
assert( bar2.c == bar.c );
assert( bar2.d == 25 );
static assert(!is(typeof( ExtendEnum!(int, "a"))));
static assert(!is(typeof( ExtendEnum!(bar, "25"))));
}
--
Simen
