[D.typesystem] Suggestion for improving OO inheritance models

[Andrej Mitrovic]

Yeah, my mistake. I missread your post. :)

But, you can use mixin expressions to add overloaded methods. E.g.:

import std.stdio;

class Bar
{
    void func()
    {
        writeln("Bar.func()");
    }

    mixin("void func(string x) { writeln(x); }");
}

void main()
{
    Bar bar = new Bar;
    bar.func();
    bar.func("test");
}

So I'm wondering if there could be an easy way to use mixin
expressions with mixin templates..

On Thu, Sep 2, 2010 at 10:17 AM, Jacob Carlborg <doob at me.com> wrote:
> On 2010-09-01 23:39, Andrej Mitrovic wrote:
>>
>> You mean like this?:
>> module add_virtual_functions;
>>
>> import std.stdio : writeln;
>>
>> void main()
>> {
>>     test();
>> }
>>
>> mixin template Foo()
>> {
>>     void func()
>>     {
>>         writeln("Foo.func()");
>>     }
>> }
>>
>> class Bar
>> {
>>     void func()
>>     {
>>         writeln("Bar.func()");
>>     }
>> }
>>
>> class Code : Bar
>> {
>>     mixin Foo;
>> }
>>
>> void test()
>> {
>>     Bar b = new Bar();
>>     b.func();   // calls Bar.func()
>>
>>     Code c = new Code();
>>     c.func();   // calls Code.func()
>> }
>>
>
> No, that is overriding. Overloading is having several methods with the same
> name taking different number of parameters or parameters of different types.
>
> module test;
>
> mixin template Foo ()
> {
>        void bar (int i) {};
> }
>
> class Bar
> {
>        void bar () {};
>        mixin Foo;
> }
>
> void main ()
> {
>        auto bar = new Bar;
>        bar.bar(4); // line 17
>        bar.bar();
> }
>
> The above code results in these errors:
>
> test.d(17): Error: function test.Bar.bar () is not callable using argument
> types (int)
> test.d(17): Error: expected 0 arguments, not 1 for non-variadic function
> type void()
>
>
>> On Wed, Sep 1, 2010 at 11:30 PM, Jacob Carlborg<doob at me.com>  wrote:
>>>
>>> On 2010-09-01 22:44, Philippe Sigaud wrote:
>>>>
>>>> On Wed, Sep 1, 2010 at 18:13, retard<re at tard.com.invalid>  wrote:
>>>>
>>>>
>>>>    Have you taken a loot at Scala&  traits already? It would be a great
>>>>    starting point.
>>>>
>>>>
>>>> Scala's traits are great! Implicits in Scala are quite interesting too.
>>>> Also, Haskell typeclasses
>>>>
>>>> I wonder if D can have part of Scala traits functionality with mixins?
>>>
>>> You can't use D template mixins to add methods that will overload
>>> existing
>>> methods.
>>>
>>>
>>> --
>>> /Jacob Carlborg
>>>
>
>
> --
> /Jacob Carlborg
>