Re: Deduct and return class type
On Saturday, 23 January 2021 at 19:19:29 UTC, Paul Backus wrote: On Saturday, 23 January 2021 at 07:17:38 UTC, Виталий Фадеев wrote: Where source ? Where deduction implementation ? Here: https://github.com/dlang/dmd/blob/v2.095.0/src/dmd/dtemplate.d#L1308 Thank!
Re: Deduct and return class type
On Saturday, 23 January 2021 at 07:17:38 UTC, Виталий Фадеев wrote: Where source ? Where deduction implementation ? Here: https://github.com/dlang/dmd/blob/v2.095.0/src/dmd/dtemplate.d#L1308
Re: Deduct and return class type
On Saturday, 23 January 2021 at 05:54:09 UTC, Виталий Фадеев
wrote:
On Saturday, 23 January 2021 at 05:39:18 UTC, Виталий Фадеев
wrote:
Context:
data + GUI List
Goal:
auto list = new List( data );
I want 'this( T )( T data )' deduction:
class A( T )
{
this( T )( T data )
{
// ...
}
}
What way to implement this ?
Rules:
1. if class is template
2. if ctor is template
3. if ctor template arg have same name with class template arg
name (example: T )
4. deduct T of ctor
5. set type T for class template ( or put in suggestion queue )
Verify, please.
Where source ?
Where deduction implementation ?
Re: Deduct and return class type
On Saturday, 23 January 2021 at 05:54:09 UTC, Виталий Фадеев
wrote:
auto listFactory( T )( T data )
{
return new List!( T )( data );
}
This is the correct way to do it in D; it's annoying, I know.
(Personally, I usually shorten `listFactory` to just `list` to
make the name as similar as possible to the type name, without
actually causing a collision.)
Re: Deduct and return class type
On Saturday, 23 January 2021 at 05:54:09 UTC, Виталий Фадеев wrote: But, how to create class instance with type deduction in usual way ? auto list = new List( extensions ); You can't; there's no type deduction for constructors.
Re: Deduct and return class type
On Saturday, 23 January 2021 at 05:39:18 UTC, Виталий Фадеев
wrote:
Context:
data + GUI List
Goal:
auto list = new List( data );
Of course, we can use 'factory':
import std.stdio;
template List( alias T )
{
class List
{
T data;
this( T data )
{
this.data = data;
}
// data usage...
}
}
auto listFactory( T )( T data )
{
return new List!( T )( data );
}
void main()
{
string[] extensions = [ ".d", ".di" ];
auto list = listFactory( extensions );
//auto list = new List( extensions );
}
source: https://run.dlang.io/is/y167tu
But, how to create class instance with type deduction in usual
way ?
auto list = new List( extensions );
Deduct and return class type
Context:
data + GUI List
Goal:
auto list = new List( data );
Concept:
class is created in the usual way : new List( data )
store inside the class: T data;
type T deducted : ( T )( T data )
Tried way:
template List( T )
{
class List
{
T data;
this( T data )
{
this.data = data;
}
// data usage...
}
}
void main()
{
string[] extensions = [ ".d", ".di" ];
auto list = new List( extensions );
}
Source: https://run.dlang.io/is/Bw2zHB
Question:
How to implement on D beauty clean flexible code ?
like a:
auto list = new List( data );
How to return from 'List( data )' class type ?
