Smart pointers instead of GC?

[Michel Fortin]

On 2014-02-04 22:30:40 +0000, Walter Bright <newshound2 at digitalmars.com> said:

> On 2/4/2014 4:23 AM, Michel Fortin wrote:
>> For the rare cases where you actually want both versions to work,
> 
> I think you're making a vast assumption that the case is rare.
> 
> When I write utility functions, I want them to work on as wide a 
> variety of inputs as possible. Otherwise, they are not very useful.

Well, if you think it's needed I won't contradict you. But that does 
not bode well for the storage class solution. If you really think it's 
needed, then you could just double the '?' to give it a similar meaning 
to inout:

	Object?? passthrough(Object?? o)
	{
		// do something here
		return o;
	}

It looks elegant to me, even if I'm not convinced it is necessary.


>> you can write them twice  or use a template (except in a virtual 
>> context), and in both cases you keep the efficiency of not checking for 
>> null when the argument is not nullable.
> 
> That's just what I wish to avoid. Consider adding more pointer types - 
> the combinatorics quickly explode. Heck, just have two pointer 
> parameters, and you already have 4 cases.

So you are already worried we'll have to add more pointer types? ;-)

Ok, let's have some fun: '#' means unique now. So we can have four 
kinds of pointers:

	Object   o1; // not-nullable & not-unique
	Object?  o2; // nullable & not-unique
	Object#  o3; // not-nullable & unique
	Object?# o4; // nullable & unique

And like above, double the marker to make it work like inout:

	Object??## passthrough(Object??## o)
	{
		// have some fun here
		return o;
	}

If you really think more pointer types will be added, then I suggest 
the implementation for this in the compiler be generic enough to 
support yes/no/maybe states for a couple of flags. Perhaps even 
user-defined flags for use by libraries (i.e. Dicebot's 
SQLEscapedString, or UnicodeNormalizedNFD, or why not PrimeNumber).

-- 
Michel Fortin
michel.fortin at michelf.ca
http://michelf.ca