[Edu-sig] Compatibility and legacy in language evolution

[Joshua Zucker]

On 9/12/06, Jan Claeys <lists at janc.be> wrote:
> Op za, 09-09-2006 te 17:53 -0700, schreef Radenski, Atanas:
> > Strictly speaking this is true, but Mr. Stroustrups own papers also
> > explain how important the full C/C++ compatibility is - and that
> > achieving it is his ideal
>
> Well, strictly speaking language A can only be fully compatible with
> language B and have more features if language B has a mechanism for
> extension that ignores unknown features.  Considering that C has no such
> mechanism, C++ will never be 100% compatible with C.

I think the point is that a C programmer can start writing C++
programs without having to change anything -- legal C programs will
still run just fine in C++.  Then the C programmer can gradually learn
whatever parts of the extensions of C++ at whatever rate, and slowly
evolve into a C++ programmer.

--Joshua Zucker