Tango BitArray Initialization

Sean Kelly sean at f4.ca
Sun Feb 11 00:28:31 PST 2007

Colin Huang wrote:
> When reading the Tango documentation, I came across this piece of code:
> import tango.core.BitArray;
> void main()
> {
>     BitArray bitbag1 = bits( 1,0,1,1,1,0 );
>     // or
>     BitArray bitbag2( 1,0,1,1,1,0 );
> }
> The documentation says that "bitbag2 is initialized such that it uses a special
 > opCall overload for the BitArray".
> Now the problem is that when I look at the source code, I don't see any overload
 > of opCall for BitArray, or any definition for the bits function. Am I
 > missing anything here?

Nope.  The documentation for tango.core was the first to be written an 
as a result it may be a bit inaccurate in places.  It would be easy to 
provide such a function however... something like this:

     BitArray bits( bool[] mask ... )
         BitArray temp;

         temp.length = mask.length;
         foreach( pos, val; mask )
             temp[pos] = val;
         return temp;

It may be even better to simply make this a ctor for BitArray, so:

     auto b = BitArray( 1, 0, 1, 0 );

> BTW, is the last line legal D code at all? It doesn't look like it's gonna
> compile (to me, at least).

The last line doesn't seem correct.  I'll give the docs a look tomorrow.


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