Unable to use template functions to define variables of a class

[Imperatorn]

On Saturday, 28 October 2023 at 12:38:42 UTC, Subhaditya Nath 
wrote:
> This works fine –

I think it's because you're using a class. Try for example:

```d
import std.range;
import std.stdio;
import std.algorithm.iteration;

void main() {
     auto cls = new Class;
     cls.range1.each!writeln;
}

class Class {
     auto range1() {
         return iota(0, 100).filter!(x => x % 2).take(25);
     }
}
```

The lambda function x => x % 2 is created within the class scope, 
which means it implicitly captures this. The filter function is a 
template that gets instantiated in a way that requires access to 
this, which is not available in the static context.

The range1 member is declared like a field within the Class, but 
it's initialized in place, outside of a constructor or method. 
This sort of initialization doesn't have access to this because 
it's not happening within an instance context (like within a 
method where this is valid).

So, then maybe you understand why it didn't work.