• ehance d.com May 14 2005
• "Uwe Salomon" <post uwesalomon.de> May 15 2005
• Chris Sauls <ibisbasenji gmail.com> May 19 2005

ehance d.com writes:

From D doc:

int test()
{
Foo f;

f.data = 3;		// same as f.data(3);
return f.data + 3;	// same as return f.data() + 3;
}

So how about:

f.data += 3;   // same as f.data( f.data()+3 )
f.data -= 3;   // same as f.data( f.data()-3 )
f.data *= 3;   // same as f.data( f.data()*3 )
f.data /= 3;   // same as f.data( f.data()/3 )

=




..

"Uwe Salomon" <post uwesalomon.de> writes:

 So how about:

 f.data += 3;   // same as f.data( f.data()+3 )
 f.data -= 3;   // same as f.data( f.data()-3 )
 f.data *= 3;   // same as f.data( f.data()*3 )
 f.data /= 3;   // same as f.data( f.data()/3 )


The op= operators are guaranteed to evaluate the lvalue only once. If you  
rewrite it the way you propose, this would not be true anymore.

Ciao
uwe

Chris Sauls <ibisbasenji gmail.com> writes:

Uwe Salomon wrote:
 f.data += 3;   // same as f.data( f.data()+3 )
 f.data -= 3;   // same as f.data( f.data()-3 )
 f.data *= 3;   // same as f.data( f.data()*3 )
 f.data /= 3;   // same as f.data( f.data()/3 )


 The op= operators are guaranteed to evaluate the lvalue only once. If 
 you  rewrite it the way you propose, this would not be true anymore.


As far as I can see, (T prop(T)) is still only being called once.  Is 
there some case wherein the Settor (T prop(T)) needs to emulate a Gettor 
(T prop()), thereby causing an internal change before the operation?  If 
not, then I don't see how its no longer true.

-- Chris Sauls