Neat trick - 'with' and unnamed objects + 'with' proposals

[BCS]

Dan wrote:
> Bill Baxter Wrote:
> 
>>    typeof(condition()) x;
>>    while(x = condition()) {
>>        // do stuff
>>    }
>>}
> 
> 
> Which is frighteningly different semantically, while being almost identical syntactically to:
> 
> while(x == condition()) {
> 
> Which is probably why Walter didn't want it to work.  It concerns me a little that if(x = 3) works.  
> 
> Honestly, D is syntactically abstracted away enough that while(something something) wouldn't have to compile down to evaluating it repeatedly.
> 
> 

if(x = 3) doesn't compile. For the If case the syntax requiters that the 
type specifier be used:

if(auto x = 3) // works
if(x == 3) // works
if(x = 3) // fails

OTOH with 'wile' the third case is totally legitimate

char x;
while(x = getc()) // scan for null and use non null in loop;

actually the proposed addition would make that error less likely, in 
fact the direct assignment could be banned in a while statement.

char x;

while(auto c = getc())
{
	x=c; // if last c needed;
	break;
}