westfw:
It's a common misconception that "Arduino" is some kind of specialized language, rather than pretty straight C++ with a bit of pre-processing applied. About all that really happens is automatic prototype generation and concatenation of the .ino files (rather than compiling each separately.) (Unfortunately, the IDE is a little clumsy about exactly where those prototypes should be added, leading to annoying incompatibilities with some common C preprocessor-directive styles...)
It also attempts to manage header files for you, which is where I suspect most of the bugs come from.
I was also under the impression it was pretty heavily subsetted version of C++ down to not much more than straight C (which of course id a proper subset of C++). And of course, a "sketch" being limited to one source file. Indeed, about the only hint that C++ is actually the underlying compiler rather than C is that class method reference constructions such as Serial.begin() are allowed. I don't think you can actually define classes within the that-which-must-not-be-named though (although I've not tried, I just went to a creating "library" *.cpp file for that whenever needed.)
FWIW, I've never really been convinced that automatically generating prototypes or managing header file inclusions are that much of a big deal that would constitute much of a benefit to novice programmers. Maybe the strict subsetting is helpful, I don't know. Is it useful or counterproductive to force beginners to put everything into one pde or ino file? Again, I don't know.
In any case, I'm just glad to have it behind me, whatever the hell that was.