Static opDispatch

[Martin Nowak]

On Sun, 02 Oct 2011 10:38:44 +0200, Jacob Carlborg <doob at me.com> wrote:

> On 2011-10-02 01:50, Steven Schveighoffer wrote:
>> On Sat, 01 Oct 2011 12:34:50 -0400, Jacob Carlborg <doob at me.com> wrote:
>>
>>> Have a look at the following code:
>>>
>>> class Foo
>>> {
>>> static Foo instance_;
>>>
>>> static Foo instance ()
>>> {
>>> if (instance_)
>>> return instance_;
>>>
>>> return instance_ = new Foo;
>>> }
>>>
>>> static auto opDispatch (string name, Args...) (Args args)
>>> {
>>> mixin("return instance." ~ name ~ "(args);");
>>> }
>>>
>>> void bar () {}
>>> }
>>>
>>> void main ()
>>> {
>>> Foo.bar;
>>> }
>>>
>>> Compiling the above code results in:
>>>
>>> Error: need 'this' to access member bar
>>>
>>> Is it possible somehow to make the above code compile?
>>
>> It's an issue with namespace polution. Both instances and the type share
>> the same namespace. It's really a bad limitation IMO. I have a bug
>> report that helps try and separate it:
>> http://d.puremagic.com/issues/show_bug.cgi?id=6579
>>
>> It should work if you use a different class as the singleton:
>>
>> class Foo2
>> {
>> void bar () {}
>> }
>>
>> class Foo
>> {
>> static Foo2 instance_;
>>
>> static Foo2 instance ()
>> {
>> if (instance_)
>> return instance_;
>>
>> return instance_ = new Foo;
>> }
>>
>> static auto opDispatch (string name, Args...) (Args args)
>> {
>> mixin("return instance." ~ name ~ "(args);");
>> }
>>
>> }
>>
>> -Steve
>
> This limitation starts to get annoying, but thanks for the workaround.
>

Changing this would invert the name lookup priority of opDispatch.
What you request makes Foo.bar inaccessible, i.e. you can't take the  
address of it any longer.

martin