On Tuesday, 6 March 2012 at 15:46:54 UTC, foobar wrote:
On Tuesday, 6 March 2012 at 10:19:19 UTC, Timon Gehr wrote:
This is quite close, but real support for non-nullable types
means that they are the default and checked statically,
ideally using data flow analysis.
I agree that non-nullable types should be made the default and
statically checked but data flow analysis here is redundant.
consider:
T foo = ..; // T is not-nullable
T? bar = ..; // T? is nullable
bar = foo; // legal implicit coercion T -> T?
foo = bar; // compile-time type mismatch error
//correct way:
if (bar) { // make sure bar isn't null
// compiler knows that cast(T)bar is safe
foo = bar;
}
of course we can employ additional syntax sugar such as:
foo = bar || <default_value>;
furthermore:
foo.method(); // legal
bar.method(); // compile-time error
it's all easily implementable in the type system.
I agree with the above and would also suggest something along the
lines of:
assert (bar) { // make sure it isn't null in debug builds
bar.method(); // legal
}
The branchy null-check would then disappear in build
configurations with asserts disabled.
