Greetings everyone,

i have the code where i have to keep pointers to so storage(context dependent stuff), so i tried declare abstract class with ctors and it didn't worked.

------- [code]

class MyContext;

abstract class MyObject
{
   // yet another bug? all descendants errors no default ctor...
   this() {}

   this(MyContext mc)
   {
   }

   MyContext _owner;
}

class MyObjectA : MyObject
{ ... }

//inside MyContext.CreateObj
MyObject CreateMyObj()
{
auto obj = new MyObjectA(this) // two errors produced

... do something with obj before returning it ...
return obj;
}

errors:
-----------
Error: no constructor for MyObjectA
Error: constructor MyObjectA.this () is not callable using argument types (MyContext)
--------

am i wrong about abstract classes usage in D or this is a bug?

On 1/8/2014 9:22 PM, evilrat wrote:
> Greetings everyone,
>
> i have the code where i have to keep pointers to so storage(context
> dependent stuff), so i tried declare abstract class with ctors and it
> didn't worked.
>
> ------- [code]
>
> class MyContext;
>
> abstract class MyObject
> {
>     // yet another bug? all descendants errors no default ctor...
>     this() {}
>
>     this(MyContext mc)
>     {
>     }
>
>     MyContext _owner;
> }
>
> class MyObjectA : MyObject
> { ... }
>
> //inside MyContext.CreateObj
> MyObject CreateMyObj()
> {
> auto obj = new MyObjectA(this) // two errors produced
>
> ... do something with obj before returning it ...
> return obj;
> }
>
> errors:
> -----------
> Error: no constructor for MyObjectA
> Error: constructor MyObjectA.this () is not callable using argument
> types (MyContext)
> --------
>
> am i wrong about abstract classes usage in D or this is a bug?

You're constructing a MyObjectA instance, not a MyObject, so the compiler is looking for a constructor in MyObjectA that takes a MyContext param.

class MyObjectA : MyObject {
   this(MyContext mc) {
      super(mc);
   }
}

On Wednesday, 8 January 2014 at 12:29:48 UTC, Mike Parker wrote:
> On 1/8/2014 9:22 PM, evilrat wrote:
>> Greetings everyone,
>>
>> i have the code where i have to keep pointers to so storage(context
>> dependent stuff), so i tried declare abstract class with ctors and it
>> didn't worked.
>>
>> ------- [code]
>>
>> class MyContext;
>>
>> abstract class MyObject
>> {
>>    // yet another bug? all descendants errors no default ctor...
>>    this() {}
>>
>>    this(MyContext mc)
>>    {
>>    }
>>
>>    MyContext _owner;
>> }
>>
>> class MyObjectA : MyObject
>> { ... }
>>
>> //inside MyContext.CreateObj
>> MyObject CreateMyObj()
>> {
>> auto obj = new MyObjectA(this) // two errors produced
>>
>> ... do something with obj before returning it ...
>> return obj;
>> }
>>
>> errors:
>> -----------
>> Error: no constructor for MyObjectA
>> Error: constructor MyObjectA.this () is not callable using argument
>> types (MyContext)
>> --------
>>
>> am i wrong about abstract classes usage in D or this is a bug?
>
> You're constructing a MyObjectA instance, not a MyObject, so the compiler is looking for a constructor in MyObjectA that takes a MyContext param.
>
> class MyObjectA : MyObject {
>    this(MyContext mc) {
>       super(mc);
>    }
> }

ok. gotta using mixins :(

On 2014-01-08 13:22, evilrat wrote:
> Greetings everyone,
>
> i have the code where i have to keep pointers to so storage(context
> dependent stuff), so i tried declare abstract class with ctors and it
> didn't worked.
>
> ------- [code]
>
> class MyContext;
>
> abstract class MyObject
> {
>     // yet another bug? all descendants errors no default ctor...
>     this() {}
>
>     this(MyContext mc)
>     {
>     }
>
>     MyContext _owner;
> }
>
> class MyObjectA : MyObject
> { ... }
>
> //inside MyContext.CreateObj
> MyObject CreateMyObj()
> {
> auto obj = new MyObjectA(this) // two errors produced
>
> ... do something with obj before returning it ...
> return obj;
> }
>
> errors:
> -----------
> Error: no constructor for MyObjectA
> Error: constructor MyObjectA.this () is not callable using argument
> types (MyContext)
> --------
>
> am i wrong about abstract classes usage in D or this is a bug?

Unfortunately constructors are not inherited.

-- 
/Jacob Carlborg

On Wednesday, 8 January 2014 at 12:40:39 UTC, evilrat wrote:
> ok. gotta using mixins :(

Just use another ctor.

class MyObjectA : MyObject
{
    this(MyContext mc)
    {
        super(mc);
    }
}

On Wednesday, 8 January 2014 at 14:01:43 UTC, Gary Willoughby wrote:
> On Wednesday, 8 January 2014 at 12:40:39 UTC, evilrat wrote:
>> ok. gotta using mixins :(
>
> Just use another ctor.
>
> class MyObjectA : MyObject
> {
>     this(MyContext mc)
>     {
>         super(mc);
>     }
> }

i do this in template. just a bit sad using mixin everywhere.