C++ filename extension

[Hans Aberg]

The Bison generated C++ parser gets by default the header filename  
extension ".hh", though GCC seems to use ".h". The idea is not bad,  
but what is the rationale for using ".hh", and should it not perhaps  
be synced with the practice on GCC?

By contrast, using ".yy", though not very important, seems to break  
the idea that the extension name indicates the language of the file  
contents. - It is essentially the same input language.

  Hans Aberg