D is a viable alternative to C++, period, not necessarily to C. I believe a rewrite of Xorg in D would be googd. The only problem with all these languages is that you cannot e.g. create a dll in Ada and generate appropriate headers to use it in C, even more in Go. In this respect I feel that this is the real problem here. The biggest obstacle is the C++ legacy code.
D is absolutely a viable alternative to C++ and probably C. There's no argument there.
D is not a viable threat to C/C++ (this is what I said!), as noone is really thinking that D will actively displace the use of C/C++ in many projects in the future. The same goes for all the other languages I mention. In my perception there's a buzz around Rust that indicates it might be viewed differently.
Can you use D without GC? How would it look like? If very restricted, then I don't see it as a viable C++ alternative.
I'm ok with GC on a web server, but coreutils are better without it.
It is possible to allocate objects in the stack (objects without polymorphism, defined with the struct keyword). No use of heap and GC in that case at all.
It's not that different to using C++ objects in the stack.
If by no GC you mean to use heap allocated objects with manually managed destructors, then I think the answer is no.
I'm looking at "http://dlang.org/garbage.html" section "D Operations That Involve the Garbage Collector", and there are some pretty interesting things on the list that require GC: all dynamic arrays, associative arrays, closures, asserts. Can you even read a file without these?
You can write the non-GC part in C and call it from D. What is the prercentage of an app that is going to get harmed by GC? I believe it is manageable in C or even FreeBasic or even Freepascal or even Assembly. I used to believe that C++ is the best. Not the last three years.
