To answer my own question... It appears that even though this code looks and quacks like C++/CLI, it actually isn't:
"In this example, you will immediately notice some keywords that are not part of standard C++. Visual C++ defines a few Component Extensions that, in a Metro style app,are essentially syntactic sugar over the underlying COM calls involved in creating and consuming Windows Runtime types.
"If you are familiar with C++/CLI, you will notice that the Component Extensions look very similar to C++/CLI syntax. However, in a Metro style app or Windows Runtime component, all the C++ code is native. The /Zw compiler option causes the Component Extensions to be compiled for Windows Runtime. The /cli compiler option causes them to be compiled for C++/CLI. Currently, C++/CLI is not supported for Metro style apps."
I'm fairly confused now. So they've added a compiler extension in Visual C++ v11 that compiles this C++/CLI look-a-like syntax into traditional COM types and calls? If so, that's good news for other compilers, I guess.
"In this example, you will immediately notice some keywords that are not part of standard C++. Visual C++ defines a few Component Extensions that, in a Metro style app,are essentially syntactic sugar over the underlying COM calls involved in creating and consuming Windows Runtime types.
"If you are familiar with C++/CLI, you will notice that the Component Extensions look very similar to C++/CLI syntax. However, in a Metro style app or Windows Runtime component, all the C++ code is native. The /Zw compiler option causes the Component Extensions to be compiled for Windows Runtime. The /cli compiler option causes them to be compiled for C++/CLI. Currently, C++/CLI is not supported for Metro style apps."
(Source: http://msdn.microsoft.com/en-us/library/windows/apps/hh45407... )
I'm fairly confused now. So they've added a compiler extension in Visual C++ v11 that compiles this C++/CLI look-a-like syntax into traditional COM types and calls? If so, that's good news for other compilers, I guess.