Hi, i have a variadic args template, with a class inside something like:

template foo(T...){


class Inner(){

...
...
}



}

Now i want to make Inner create or i will create manually, constructor for each of T... parameter types, but don't know what is syntax for it. I found that there is possibility to initialize T... types static variables with AliasSeq!(T) but how to do this automatically, or with static ifs,for constructors ?
I tried ...

template foo(T...){
alias Types=AliasSeq!(T);
Algebraic!(T) value;
this(Types value)
this.value=value;
}
}
But this dosn't work

On Saturday, 6 February 2016 at 18:05:05 UTC, Voitech wrote:
> Hi, i have a variadic args template, with a class inside something like:
>
> template foo(T...){
>
>
> class Inner(){
>
> ...
> ...
> }
>
>
>
> }
>
> Now i want to make Inner create or i will create manually, constructor for each of T... parameter types, but don't know what is syntax for it. I found that there is possibility to initialize T... types static variables with AliasSeq!(T) but how to do this automatically, or with static ifs,for constructors ?
> I tried ...
>
> template foo(T...){
> alias Types=AliasSeq!(T);
> Algebraic!(T) value;
> this(Types value)
> this.value=value;
> }
> }
> But this dosn't work

This gives  Error: memcpy cannot be interpreted at compile time, because it has no available source code

On 02/06/2016 10:05 AM, Voitech wrote:

> create manually, constructor
> for each of T... parameter types

You can use string mixins (makeCtor and makeCtors):

string makeCtor(T)() {
    import std.string : format;

    return format(q{
        this (%s t) {
            import std.stdio : writefln;
            writefln("Ctor for %%s", %s.stringof);
        }
        }, T.stringof, T.stringof);
}

// Note: Use a pragma(msg) to see what it generates:
// pragma(msg, makeCtor!int);

string makeCtors(T...)() {
    string result;
    foreach (Type; T) {
        result ~= makeCtor!Type();
    }
    return result;
}

mixin template foo(T...) {

    class Inner {
        mixin (makeCtors!T());
    }
}

mixin foo!(int, string);

void main() {
    auto i = new Inner(42);
    auto s = new Inner("hello");
}

Output:

Ctor for int
Ctor for string

Ali

On Saturday, 6 February 2016 at 23:35:17 UTC, Ali Çehreli wrote:
> On 02/06/2016 10:05 AM, Voitech wrote:
>
> > [...]
>
> You can use string mixins (makeCtor and makeCtors):
>
> string makeCtor(T)() {
>     import std.string : format;
>
> [...]

Thank you very much for answering.
Cheers

On Monday, 8 February 2016 at 07:08:58 UTC, Voitech wrote:
> On Saturday, 6 February 2016 at 23:35:17 UTC, Ali Çehreli wrote:
>> On 02/06/2016 10:05 AM, Voitech wrote:
>>
>> > [...]
>>
>> You can use string mixins (makeCtor and makeCtors):
>>
>> string makeCtor(T)() {
>>     import std.string : format;
>>
>> [...]
>
> Thank you very much for answering.
> Cheers

Unfortunately this doesn't work as I'am trying to assign value from ctor to member something like:

this(%s value){
    this.value=value;
}

it gives me
Error: memcpy cannot be interpreted at compile time, because it has no available source code.
Probably this is caused by declaration of member which is also parametrized with T...
Member is:
Algebraic!(T) value;

So declaration of this mixin constructors are done before variable value is declared (compilation)?

Is there any field in class that would contain ctors ? Something like __ctors ?
i could try to init this(T... value) constructors in static constructor using delegates/functions. Something like:

template Outer(T...){
class Inner{
		Algebraic!(T) value;

		alias ctor(Type) =Inner delegate (Type value);
		static this(){
			foreach(Type;T){
				ctor!(Type) c={
					this.value=value;
				};
                        __ctors~=c; // ?????
			}

		}

}

http://dpaste.dzfl.pl/1f25ac34c1ee
You need Tuple, not Algebraic. Algebraic stores only one value of one type from a set, like Variant.

On Monday, 8 February 2016 at 15:09:30 UTC, Kagamin wrote:
> http://dpaste.dzfl.pl/1f25ac34c1ee
> You need Tuple, not Algebraic. Algebraic stores only one value of one type from a set, like Variant.

Thank you for answering. You right if i would want to store all types of T.. in an Inner instance. But my conception was bad from the beginning. I want to store only one type of value in Inner instance. I just wanted to create generic constructor for each of Type which is invalid, cause instance holds value of single type that's why it is not parametrized by itself.