On 28.05.2012 12:58, Denis Shelomovskij wrote:
27.05.2012 23:45, bearophile написал:
In some code I have created a small bug that can be reduced to something
like this, that the D compiler has not caught at compile-time:
enum E1 { A, B }
enum E2 { C, D }
void main() {
E1[2] a;
with (E2)
assert(a[0] == D);
}
Why isn't D able to statically tell when you compare values of different
enums?
How much work is implementing this compile-time test inside the D
front-end?
Thank you,
bye,
bearophile
Enumerations are in very poor state in D now. May be, it should be
deprecated just like typedef and be library-implemented. Why? Because we
do need really strict type/operation checking with enum so one have to
write explicitly casts to do non-standard things. The two main
enumeration types are:
* list - must hold only one value, only opAssign and opEqual are
allowed, by default nextValue = prevValue + 1 starting with 0
* flags - must hold superposition of values, like list, but binary
operations are also allowed, by default nextValue = prevValue << 1
starting with 1
+1. Well said, hard to add anything ;)
These also allow finally implement right to!string for flags.
By the way, current enums can be modified to correspond "list"
enumeration and flags can be added as library component.
--
Dmitry Olshansky
