"Rubinius switched from C to C++ to implement it's core VM"
For the life of me I cannot understand why projects use C++ rather than Objective-C. Hmm.
Catching up on comments to this post...
Yeah, I can be too brief sometimes. Here's the essence of what I like about ObjC vs. C++. ObjC attempts to keep the Obj and the C distinct, while C++ attempts to combine them. As a result the Obj in ObjC is very much like the Obj in Smalltalk. And the C on Obj C is very much like the C in ANSI C.
The Obj in C++ is significantly more complicated than the Obj in Smalltalk or in ObjC. The C in C++ is also significantly more complicated, to the point where I don't think it can be called "C". People will talk about the expressiveness of C++ and how much it has evolved over the years. I still very much prefer the simplicity of ObjC.
I am also surprised the ObjC has portability issues. With the GNU implementation?
And I am surprised about the Ruby kernel issue as well. I also thought this would be so small to warrant just C or even better, a subset of Ruby that compiles easily into C. This is what Squeak uses for its kernel. Gambit Scheme does something along the same lines, allowing a very C-ish dialect of Scheme that translates directly.