Pointers vs. References

[Bill Baxter]

Ary Manzana wrote:
> Lionello Lunesu escribió:
>> That's not a bug.
>> '==' and '!=' result in a call to opEquals, which is likely to 
>> segfault when one of the operands is null. You should use 'is' or in 
>> your case '!is'.
> 
> Can't writing
> 
> x == null, x != null
> 
> be rewritten by the compiler to
> 
> x is null, x !is null
> 
> ?
> 
> 
> I think the two firsts will always segfault. When would a user want to 
> segfault her program? Or, better asked, when would a user want to do x 
> == null?
> 
> Regards,
> Ary

Why not have the compiler just rewrite all equality comparisons on class 
objects?

    x == y    ===>    (x is y || x.opEquals(y))

I mean you might as well check first that they aren't the same object, 
because if they are then obviously they are equal too[1].   That would 
make the behavior the norm and not a special case.  I don't see how 
doing one extra pointer comparison is going to significantly affect 
performance.

But then I guess there's that bizzarro-business about opEquals returning 
an int because that's "more efficient".  So I guess someone is 
hypersensitive about object equality operations being as fast as possible.

--bb

[1] Unless you're trying to implement some weirdo NaN like object which 
is not equal to anything, including itself.