Re: iterating through members of bitfields

[Ali Çehreli via Digitalmars-d-learn]

On 01/17/2017 04:37 PM, Nestor wrote:
Hi,
I was just looking at an interesting function from
http://codepad.org/lSDTFd7E :

void printFields(T)(T args) {
  auto values = args.tupleof;

  size_t max;
  size_t temp;
  foreach (index, value; values) {
    temp = T.tupleof[index].stringof.length;
    if (max < temp) max = temp;
  }
  max += 1;
  foreach (index, value; values) {
    writefln("%-" ~ to!string(max) ~ "s %s", T.tupleof[index].stringof,
value);
  }
}

Can something similar be done for bitfields? I tried running this and I
only get something like this:

_f01_f02_f03      25312
_f04_f05_f06_f07  21129
_f08_f09_f10      53575
_f11_f12_f13_f14  9264


Not available but it should be possible to parse the produced code:

import std.bitmanip;

string makeBitFieldPrinter(string fieldImpl) {
    return q{
        void printBitFields() const {
            import std.stdio: writeln;
            writeln("Please improve this function by parsing fieldImpl. 
:)");
        }
    };
}

struct S {
    enum myFields = bitfields!(int, "a", 24,
                               byte, "b", 8);

    pragma(msg, "This is the mixed-in bit field code\n---------\n",
           myFields, "\n----------");


    mixin (myFields);
    mixin (makeBitFieldPrinter(myFields));
}

void main() {
    const s = S();
    s.printBitFields();
}

Of course that would depend on the implementation of bitfields(), which 
can change without notice.

Ali