• Andrej Mitrovic (4/4) Feb 18 2013 http://dlang.org/template.html#TemplateThisParameter
• Steven Schveighoffer (20/24) Feb 18 2013 I actually use it in dcollections :)
• Andrej Mitrovic (2/3) Feb 18 2013 Ah, that sheds a big light on this feature actually, thanks.
• Lee Braiden (23/28) Feb 23 2013 I guess it's for doing things like:

Andrej Mitrovic <andrej.mitrovich gmail.com> writes:

http://dlang.org/template.html#TemplateThisParameter

That's hardly a descriptive example, so in what context is the feature
useful? Some code snippets would be welcome so we can update the page
with a nicer and more useful example.

"Steven Schveighoffer" <schveiguy yahoo.com> writes:

On Mon, 18 Feb 2013 17:14:54 -0500, Andrej Mitrovic  
<andrej.mitrovich gmail.com> wrote:

 http://dlang.org/template.html#TemplateThisParameter

 That's hardly a descriptive example, so in what context is the feature
 useful? Some code snippets would be welcome so we can update the page
 with a nicer and more useful example.

I actually use it in dcollections :)

What it's nice for is simulating covariance with interface templates:

interface Addable(T)
{
   auto addAll(this R)(T[] stuff)
   {
      foreach(t; stuff) add(t);
      return cast(R)this;
   }

   Addable add(T t);
}


class List(T) : Addable!(T)
{
    List add(T t) { ... }

    // don't need to redefine addAll
}

This became important when operators were forced to be templates.

-Steve

Andrej Mitrovic <andrej.mitrovich gmail.com> writes:

On 2/19/13, Steven Schveighoffer <schveiguy yahoo.com> wrote:
     // don't need to redefine addAll

Ah, that sheds a big light on this feature actually, thanks.

Lee Braiden <leebraid gmail.com> writes:

On Mon, 18 Feb 2013 23:14:54 +0100, Andrej Mitrovic wrote:

 http://dlang.org/template.html#TemplateThisParameter
 
 That's hardly a descriptive example, so in what context is the feature
 useful? Some code snippets would be welcome so we can update the page
 with a nicer and more useful example.

I guess it's for doing things like:

import std.stdio;

class Mammal {
    void printDescription(this T)()
    {
        writeln(typeid(T));
    }
};

void main(string[] args)
{
    class Dog : Mammal {};
    class Cat : Mammal {};

    auto a = new Dog();
    auto b = new Cat();

    a.printDescription();
    b.printDescription();
}


Outputs:

hello.main.Dog
hello.main.Cat


-- 
Lee