using assignment statement as conditional in a where

[dan via Digitalmars-d-learn]

In c, you can have code like this:

static void wtest( void ) {
   int f;
   while ( ( f = some_val( ) ) ) {
     printf(" our value is now: %d\n", f );
   }
}

gcc compiles this without warning or error (at least if you use 
the double parentheses to assure the compiler that you realize 
you are testing an assignment, not a comparison).

I would like to do the same thing in d, something like this:

private void wtest( ) {
   int f;
   while ( ( f = some_val( ) ) ) {
     writeln(" our value is now: ", f );
   }
}

or even better:

private void wtest( ) {
   while ( ( auto f = some_val( ) ) ) {
     writeln(" our value is now: ", f );
   }
}

This however does not work, and the gdc compiler says "assignment 
cannot be used as a condition, perhaps == was meant?"

I don't absolutely have to do it this way, as i guess i could do 
'while (true) {...' and then break if the assignment returns zero.

But i really, really would like to use the idiom of assigning a 
value from inside a while condition.

Is it possible to do this?  Perhaps with extra braces or 
something, like while ( {something here} ) { .... } ?

TIA for any pointers or advice.

dan