MacApp significantly predates NEXTSTEP.
I would even go as far as to say that NEXTSTEP is basically a copy of MacApp.
Also MacApp is still maintained and developed (though not by Apple). It uses modern C++, it’s robust, it scales well, it supports Mac OS 9 through Leopard & Windows and its full source code is available to study & modify (which, personally, I find more useful than Apple’s documentation).
by The Doctor — Mar 06
I would even go as far as to say that NEXTSTEP is basically a copy of MacApp.
Also MacApp is still maintained and developed (though not by Apple). It uses modern C++, it’s robust, it scales well, it supports Mac OS 9 through Leopard & Windows and its full source code is available to study & modify (which, personally, I find more useful than Apple’s documentation).