These features are only enabled in low-level contexts. Currently this only includes Repl submissions.
Structures are less feature rich but more efficient classes. Eventually, the compiler will automatically rewrite classes]] into structures if possible to optimize, but this is currently unsupported.
Structures only allow field declarations with no initializers. Fields within structures cannot be constants or references.
struct MyStruct {
int a;
string b;
}
Creating a new instance of a structure uses the same new keyword as classes, but the constructor cannot be overridden
and always takes no arguments:
var myInstance = new MyStruct();
Because of this, all fields must manually be written to after structure creation:
myInstance.a = 3;
myInstance.b = "Hello";