Multiple namespace declaration in C++

Question

Is it legal to replace something like this:

namespace foo {
   namespace bar {
      baz();
   }
}

with something like this:

Answer 1

Pre C++17:

No, it's not. Instead of a bunch of indented nested namespaces, it's certainly valid to put them on the same line:

namespace Foo { namespace Bar { namespace YetAnother {
    // do something fancy
} } } // end Foo::Bar::YetAnother namespace

C++17 Update:

You can now nest namespaces more cleanly in C++17:

namespace Foo::Bar::YetAnother {
  // do something even fancier!
}