Hi,

As the documentation at D ONLY shows template at functions level and also ONLY the content of a class but without the definition of a class.
Could this code be working? Or did I miss out some syntax.

mixin template AType(alias T, U, alias V){
class T : ClassC { // Class level Template
private:
    U value;
public:
    this(){}
    void print(){}
        mixin V;
} // End Class
}

class ClassC {}

mixin template btype() {
    void someFunction() {}; // Content of a class.

}

mixin AType!("ClassB", string, btype);

void main() {
    ClassC r = new ClassB();
}


--------  Build Commands:  --------
-od"bin"
-of"bin\TestTemplate.exe"

-I"src"

"src\Sample.d"

src\Sample.d(20): Error: undefined identifier ClassB, did you mean class ClassC?
src\Sample.d(20): Error: ClassB is used as a type

Thanks very much for helping out.

-- 
Matthew Ong
email: ongbp@yahoo.com

On Sat, 21 May 2011 10:54:54 +0200, Matthew Ong <ongbp@yahoo.com> wrote:

> mixin template AType(alias T, U, alias V){
> class T : ClassC { // Class level Template

This gives you a class called T. You seem to want it to have the name
you pass as a string, in which case you have to use string mixins.

> private:
>      U value;
> public:
>      this(){}
>      void print(){}
>          mixin V;
> } // End Class
> }
>
> class ClassC {}
>
> mixin template btype() {
>      void someFunction() {}; // Content of a class.
>
> }
>
> mixin AType!("ClassB", string, btype);
>
> void main() {
>      ClassC r = new ClassB();
> }

As mentioned above, in order to use the name from the template parameter
you need to use string mixins. Here is how I would do it:

string ATypeGenerator( string name ) {
    return "class " ~ name ~ " : ClassC {
private:
    U value;
public:
    this(){}
    void print(){}
    mixin V;
}";
}

mixin template AType( string name, U, alias V ) {
    mixin( ATypeGenerator( name ) );
}

mixin AType!("ClassB", string, btype);

void main() {
    ClassC r = new ClassB();
}


-- 
Simen

On 5/21/2011 5:12 PM, Simen Kjaeraas wrote:
> On Sat, 21 May 2011 10:54:54 +0200, Matthew Ong <ongbp@yahoo.com> wrote:
>
>> mixin template AType(alias T, U, alias V){
>> class T : ClassC { // Class level Template
>
> This gives you a class called T. You seem to want it to have the name
> you pass as a string, in which case you have to use string mixins.
>
>> private:
>> U value;
>> public:
>> this(){}
>> void print(){}
>> mixin V;
>> } // End Class
>> }
>>
>> class ClassC {}
>>
>> mixin template btype() {
>> void someFunction() {}; // Content of a class.
>>
>> }
>>
>> mixin AType!("ClassB", string, btype);
>>
>> void main() {
>> ClassC r = new ClassB();
>> }
>
> As mentioned above, in order to use the name from the template parameter
> you need to use string mixins. Here is how I would do it:
>
> string ATypeGenerator( string name ) {
> return "class " ~ name ~ " : ClassC {
> private:
> U value;
> public:
> this(){}
> void print(){}
> mixin V;
> }";
> }
>
> mixin template AType( string name, U, alias V ) {
> mixin( ATypeGenerator( name ) );
> }
>
> mixin AType!("ClassB", string, btype);
>
> void main() {
> ClassC r = new ClassB();
> }
>
>
Hi, Thanks for the respond.
I am really new to D.
Using your code I have this error:

src\Sample.d(16): Error: undefined identifier btype, did you mean template AType(string name,U,alias V)?
src\Sample.d(16): Error: mixin AType!("ClassB",string,_error_) does not match template declaration AType(string name,U,alias V)

Could you please ensure it is compilable code and so that I can test the template shown by you.

-- 
Matthew Ong
email: ongbp@yahoo.com

On Sat, 21 May 2011 11:40:22 +0200, Matthew Ong <ongbp@yahoo.com> wrote:

> Using your code I have this error:
>
> src\Sample.d(16): Error: undefined identifier btype, did you mean template AType(string name,U,alias V)?
> src\Sample.d(16): Error: mixin AType!("ClassB",string,_error_) does not match template declaration AType(string name,U,alias V)
>
> Could you please ensure it is compilable code and so that I can test the template shown by you.

Sorry about that.


string ATypeGenerator( string name ) {
    return "class " ~ name ~ " : ClassC {
private:
    U value;
public:
    this(){}
    void print(){}
    mixin V;
}";
}

mixin template AType( string name, U, alias V ) {
    mixin( ATypeGenerator( name ) );
}

class ClassC {}

mixin template btype() {
    void someFunction() {}; // Content of a class.
}

mixin AType!("ClassB", string, btype);

void main() {
    ClassC r = new ClassB();
}

-- 
  Simen

On 5/23/2011 2:17 AM, Simen Kjaeraas wrote:
> On Sat, 21 May 2011 11:40:22 +0200, Matthew Ong <ongbp@yahoo.com> wrote:
>
>> Using your code I have this error:
>>
>> src\Sample.d(16): Error: undefined identifier btype, did you mean
>> template AType(string name,U,alias V)?
>> src\Sample.d(16): Error: mixin AType!("ClassB",string,_error_) does
>> not match template declaration AType(string name,U,alias V)
>>
>> Could you please ensure it is compilable code and so that I can test
>> the template shown by you.
>
> Sorry about that.
>
>
> string ATypeGenerator( string name ) {
> return "class " ~ name ~ " : ClassC {
> private:
> U value;
> public:
> this(){}
> void print(){}
> mixin V;
> }";
> }
>
> mixin template AType( string name, U, alias V ) {
> mixin( ATypeGenerator( name ) );
> }
>
> class ClassC {}
>
> mixin template btype() {
> void someFunction() {}; // Content of a class.
> }
>
> mixin AType!("ClassB", string, btype);
>
> void main() {
> ClassC r = new ClassB();
> }
>
Thanks simen. I have solve that issue.

Someone also pointed out:

template mydef(string name){
}

mixin(mydef!("abc"));

The above are NOT shown up left hand side of that when we click on Language Reference
http://www.digitalmars.com/d/2.0/lex.html
And also here.
http://www.digitalmars.com/d/2.0/comparison.html

not the same as:
mixin template mydeff(T){
...
}

mixin mydeff!(string);

Some centralized documentation is needed for D.

-- 
Matthew Ong
email: ongbp@yahoo.com

On 5/23/11, Matthew Ong <ongbp@yahoo.com> wrote:
> Someone also pointed out:
>
> template mydef(string name){
> }
>
> mixin(mydef!("abc"));
>
> The above are NOT shown up left hand side of that when we click on Language Reference

You're probably looking for this:

http://www.digitalmars.com/d/2.0/mixin.html