On 02/11/2012 08:48 AM, Jonathan M Davis wrote:
On Friday, February 10, 2012 22:41:20 Ellery Newcomer wrote:
dmd 2.057
Two mixin templates, each define toString, mix them in to your class and ..
Error: function test.X.T2!().toString multiple overrides of same function
So this behavior is new, but is it sensical?
Sample code:
mixin template T1(){
string toString(){
return "1";
}
}
mixin template T2(){
string toString(){
return "2";
}
}
class X{
mixin T1!() a;
mixin T2!() b;
}
void main(){
}
And why _wouldn't_ that be an error? You have to identical function
signatures.
In different scopes.
class X
{
string toString() { return "1"; }
string toString() { return "2"; }
}
isn't legal. What's the difference between that and your mixins?
And can template mixins mixin virtual functions? Normally, templated functions
can't be virtual (template mixins are instantiated regardless, so they might
be virtual when mixed into classes - I'm not sure). And if template mixins
aren't virtual, then _both_ mixins should be illegal, since Object already
have a virtual toString in it.
template mixins can mixin virtual functions. Just like template classes
can have virtual functions.
Regardless, I don't see how you could think that your code would be legal.
It probably should not be, but this certainly should be legal:
class X{
mixin T1!() a;
mixin T2!() b;
alias a.toString toString;
}
Yet, it yields the same error. The subject seems to be quite moot: If a
subclass overrides a function declared in multiple named template
mixins, the first one declared is overridden. I don't really know how it
should work. The spec is not detailed enough on this. The current
behaviour is certainly wrong though.
