proper bit fields in the D2 language?

[Andrei Alexandrescu]

Mattias Holm wrote:
>> Except that bitfields don't appear to be a widely used feature.
> 
> You clearly have not written systems code in Ada... :)
> 
> C-bitfields are problematic because the bit-ordering is implementation 
> defined, GCC have the bits appear in the order of definition on 
> big-endian machines and the reverse order on little endian machines. The 
> appropriate way is to have them as the big-endian fields in GCC, this is 
> also what most Ada-compilers seem to be doing.
> 
> They are incredibly useful for any systems and protocol programming, and 
> this is why they are nice to have in a language like D.
> 
> Bitfields are not used in C because they are not platform neutral, a 
> proper definition in D would mean that people would use them, at least 
> in the mentioned domains.

Bitfields in Phobos are defined portably: always populated from lsb to 
msb, the total size must be 8, 16, 32, or 64, and there is no hidden 
padding (you obtain padding with anonymous fields).

Andrei