> Which is why I STRONGLY recommend using only the lightest-weight parts of
> C++ that offer the greatest benefits. I haven't looked at ObjectiveC that
> closely, but remember that Next did write nearly an entire OS in that
> language, and it ran quite well. Something to look at as an example of
> high-performance system-level OO.
I am lurker on this list, but having worked almost exclusively with
NeXT products (NeXTstep 2.x / 3.x / OPENSTEP 4.2 / YB-Windows / Mac OS
X Server / Mac OS X ) since 1991, this is an area I know quite well :-)
To make a long story short, NeXT did not 'implement an entire OS' in
ObjC. The Mach kernel / libc were in raw C + assembly. The other big
non-objc component was the display PostScript window server.
The objc runtime was linked to the kernel, so objc could be used in device
drivers, but that was all. Apple's Darwin is basically NeXTstep, so the
sources are now avalaible. ObjC also did a few appearance in basic command
line tools.
What was in objc, in the first versions (ie: up to NS3.3), was only the
GUI stuff (aka AppKit. Quite similar to KDE or gnome) and the user
applciations. In the later version (OPENSTEP 4.x), the FoundationKit
appeared, and provided objc basic services. Foundation services are
conceptually similar to libc (but an order of magnitude more powerfull).
The performance and memory hit have been *huge* (but well worth it)
Cheers,
--fred
