bitfield - 4935/4937 Allow repeated (identical) bitfield declarations

[Era Scarecrow]

repost from issue list:

Austin Hastings 2010-09-24 18:06:53 PDT
Also, I think I'm going to request that repeated bitfield 
definitions be allowed if they are identical - I'd like to 
redeclare "opcode" rather than "".

How would you tell them apart? If I know how you may want to call 
them, I may
be able to make something. I can understand with registers, but 
still need some
way to work with them. Perhaps as a set then?

So I would like the bitmanip code to permit redeclaration of 
bitfields that are identical in all respects.

That is, obviously the names are the same, but the field width, 
offset, and type representation has to be the same as well.

Maybe....?

struct S {
    mixin(bitfields!(
        uint, "opcode", 4,
        uint, "register", 4,
        uint, "register", 4,
        uint, "register", 4
    ));
}

and using the registers would have function signature like...

struct Register {
  uint register_1;
  uint register_2;
  uint register_3;

}

//setters, likely can't be @propery
void register(uint reg1, uint reg2, uint reg3);
void register(uint[] register ...); //maybe?
void register(Register register);

//getter ??
Register register() const;

Or perhaps...

struct S {
    mixin(bitfields!(
        uint, "opcode", 4,
        uint, "reg1", 4,
        uint, "reg2", 4,
        uint, "reg3", 4
    ));
    mixin(sharedNameSet(
        "nameForGetterAndSetter",
        "struct name for returning/passing",
        "reg1", "reg2", "reg3" //named variables as a set
    ));

    //nameForGetterAndSetter's would be added here, perhaps as 
above.
}