What is :-) ?

[evilrat]

On Monday, 20 November 2023 at 16:09:33 UTC, Antonio wrote:
>
> Is there any way to force D compiler to treat this 
> "createCounter" declaration as **delegate** instead of 
> **function**?
>
> ```d
>   auto createCounter = (int nextValue) => () => nextValue++;
> ```

generally there is a way to tell the compiler specifically that 
you want a delegate or a function, and additionally there is 
`toDelegate` function from std.functional that could be useful in 
some cases.

https://dlang.org/phobos/std_functional.html#toDelegate


the syntax for specifying delegate/function is smth like this, 
IIRC return type can be omitted but for reference I write it here 
as auto.

```d
// this is a function returning a delegate
auto createCounter(int nextValue) => auto delegate() => 
nextValue++;

// this is a function returning a function
auto createCounter(int nextValue) => auto function() => 
nextValue++;
```