I read that Dart does not support function overloading. Does it support operator overloading? If yes, can you show me how it's done in a simple example? And what are some advantages etc?
The chosen answer is no longer valid when you try overloads using the ==
operator in the new version. Now you need to do this:
class MyClass {
@override
bool operator ==(other) {
// compare this to other
}
}
But it's not safe. other
is not specified as a type, Something unexpected may happened. For example:
void main() {
var a = A(1);
var b = B(1);
var result = a == b;
print(result); //result is true
}
class A {
A(this.index);
final int index;
@override
bool operator ==(other) => other.index == index;
}
class B {
B(this.index);
final int index;
}
So you could do like this:
class A {
A(this.index);
final int index;
@override
bool operator ==(covariant A other) => other.index == index;
}
You need to use covariant
. Because Object overloads the ==
operator.
Test Object Type:
visit: hash_and_equals
class A {
A(this.index);
final int index;
@override
bool operator ==(other) => other is A && (other.index == index);
@override
int get hashCode => index;
}