`do` and `for` blocks

There are two ongoing trends in the mulle libraries. One is to wrap short lived data structures into a “do” block. The other is to hide the enumerators in “for” blocks.

As an example, lets write a function, that accepts some variable arguments, puts them into a mulle_pointerarray. Then the array is reverse enumerated, and the contents printed line by line:

static void  reverse_print( FILE *fp, ...)
{
   va_list  args;
   char     *s;
   char     *item;

   va_start( args, fp);
   mulle_pointerarray_do( array)
   {
      // fill array with arguments
      while( (s = va_arg( args, char *)))
      {
         mulle_pointerarray_add( array, s);
      }

      // now go from back to front and print
      mulle_pointerarray_for_reverse( array, item)
      {
         fprintf( fp, "%s\n", item);
      }
   }
   // the array contents are freed and variable "array" is undefined outside
   // of the block
   va_end( args);
}

The opportunities for bugs aren’t eliminated, but things look tidier and tighter.

All data structures of mulle-container now can be used in this “do/for” manner. And many other data structures in other parts of mulle-core and even the MulleFoundation (like NSLockingDo) partake in the scheme.