Jonathan Marler:
if we allow return value types to be written as "auto" then it
makes since to have cast(auto) as well.
I think "cast(auto)" as I understand in your proposal introduces
too often undefined situations, because in many cases the
compiler can't know what's the type to cast to, and guessing is
not acceptable. So I think it's not a good idea.
But sometimes I have code like this:
void main() {
int x;
byte y;
// ...
y = cast(typeof(y))x;
}
Here I want to cast x to the type of y to allow the assignment to
y. This is perhaps an acceptable semantics for "cast(auto)":
void main() {
int x;
byte y;
// ...
y = cast(auto)x; // OK
}
In that case the inference for the casting type is easy because
the type of y is already defined. More examples:
void foo(byte z) {}
void main() {
int x;
// ...
auto y = cast(auto)x; // Error
byte y = cast(auto)x; // OK, but not very useful
foo(cast(auto)x); // OK
}
Bye,
bearophile
