What is the "Final"?
Rikki Cattermole via Digitalmars-d-learn
digitalmars-d-learn at puremagic.com
Tue Jan 20 04:02:12 PST 2015
On 21/01/2015 12:58 a.m., RuZzz wrote:
> Alexandrescu "The_D_Programming_Language"
> page 264: 7.1.10 Subtyping with structs. The @disable Attribute
> import std.stdio;
> ...
> unittest {
> auto a = Final!Widget(new Widget);
> a.print(); // Fine, just print a
> auto b = a; // Fine, a and b are bound to the same Widget
> a = b; // Error!
> // opAssign(Finai!Widget) is disabled!
> a = new Widget; // Error!
> // Cannot assign to rvatue returned by get()!
> }
>
> What is the "Final" in the code?
I'm guessing something along these lines:
struct Final(T) {
private T value;
alias value this;
this(T value) {
this.value = value;
}
@disable
void opAssign(T)(T t) {}
}
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