On Thursday, 31 January 2013 at 14:47:17 UTC, TommiT wrote:
[..]
Although, it's just not very healthy to be passing those property
variables around, because it enables writing all kinds of bugs:
struct S
{
int n;
property Prop
{
@property int get() { return outer.n; }
alias this = get;
Prop opAssign(string S : "+")(int v)
{
outer.n += v;
return this;
}
}
Prop prop;
}
void foo(T)(T t)
if (isImplicitlyConvertible!(T,int))
{
auto v = t;
v += 1; // calls t.prop.opAssign!"+"(1)
// given: is(T == S.Prop)
}
...
S s;
foo(s.prop); // increments S.n, not good
So, I guess properties need to be magic, they're not imaginable
as a some kind of restricted + augmented structs. The crux of the
matter is the alias this which is needed for implementing the
getter (accessor) of the property. The property variable should
*not* be convertible to getter, but the property variable itself
should be the getter.
