Christoph Seifert wrote:
>
> thank you very much for your comment!
>
> I think my statement might have been a bit confusing.

Not so much confusing as incomplete.  A specific example
or two that compared to 'old way' and the 'new way' would
probably make things clearer.

> I still think, that an implementation as in the standard
 > library with enum, declarations of variables and declaration
> of bitwise operators is akward at best and lengthy at the
 > very least.

Yep, but I don't think it will work as a library item.  I
get the impression that this is a language issue.  Adding
keywords generally is.

> ...
>
> Your proposal aims at the portability of bitfields for
 > use with hardware interfaces.  This I think is a different,
 > though very important field.

Hmm.  I think I failed to make something clear.  The hardware
interface requirements are more restrictive than the information
packing requirements and thus drive the specifications.  However
both sets of needs should be addressed.

----------

I've been thinking about what I proposed and think at least two
additions are called for.

1) With the understanding that the names of the 'special members'
    are only suggestions, the value of (1 << field.bit) should also
    exist and could be called '.lsb'.

2) There should be a way to allocate all the remaining bits in a
    store without knowing exactly how many bits that is.  The
    syntax ': ...' might be viable.

There is also the type safety issue.  Bitwise operations on a
store associated with bit-fields should be restricted to
expressions that must include 'special members' values from
those bit-fields in appropriate contexts.  In effect each such
store should have restrictions similar to those associated with
a user defined type.  Wording this properly could be difficult.

max@mtew.isa-geek.net

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