On 12 May 2012 12:37, Jonathan M Davis <jmdavisp...@gmx.com> wrote:
> On Saturday, May 12, 2012 11:26:37 Timon Gehr wrote:
> > On 05/12/2012 10:13 AM, Manu wrote:
> > > On 11 May 2012 21:28, Mehrdad <wfunct...@hotmail.com
> > >
> > > <mailto:wfunct...@hotmail.com>> wrote:
> > > Yes, I agree, but consider that D users should NOT have to work
> with
> > > pointers to do something so basic
> > >
> > > I'd like to think this were true, but the fact that 'ref' barely works
> > > makes this almost immediately false when trying to write any
> non-trivial
> > > program.
> >
> > It depends on the coding style.
>
> I rarely end up passing by either ref or pointer, and the only issues that
> I've ever had with ref relate to the fact that you can't pass it rvalues.
> Obviously both pointers and ref have their uses, but I'd definitely have to
> concur that it depends on your coding style and what you're doing. Also, I
> really don't know what's wrong with ref such that anyone could say that it
> "barely works" other than the issues with rvalues and functions which take
> ref
> or const ref.
>
struct X
{
int i;
X opBinary(string op)(const ref X b) if(op == "+") { return X(i + b.i); }
ref X opOpAssign(string op)(const ref X b) if(op == "+") { i += b.i; return
this; }
...etc
}
ref X func(ref X x)
{
return x;
}
bool maybe()
{
return (time() & 1) != 0;
}
void test()
{
X a,b,c;
X v[];
func(a); // this is basically the only expression that works
X t = a + (b + c); // fail
a += b + c; // fail
ref X t = func(a); // fail
func(a + b); // fail
func(maybe() ? a : b); // this generates bad code:
http://forum.dlang.org/thread/cnwpmhihmckpjhlas...@forum.dlang.org
ref X t = v[some + complex * (expression + that_i_dont_want_to_repeat())];
// fail
foreach(i; 0..10)
{
ref X t = v[some + expression * involving - i]; // fail
}
}
Just a couple of extremely common usage patterns that come to mind. I'm
sure there are many more...
