Design question regarding saving changes in the original array and/or returning a new set

[Paul Backus]

On Sunday, 23 October 2022 at 13:32:44 UTC, matheus wrote:
> I have a design question and I'd like to hear some advice. 
> Let's say that I want to create a method to sort an array:
>
>     arr.sort(asc);
>
> I think usually this would usually return a new set of that 
> array but now sorted.
>
> But If I want to do this in the original, I think I would do 
> this:
>
>     arr.sort(asc).save();
>
> The problem with this, it would create a new set and 
> assign/copy back to the caller, which would be a waste. So I 
> thought about this:
>
>     arr.save.sort(asc);
>
> Then save would tell to "sort()" what to do beforehand, like 
> passing some argument saying that the sort should be done 
> direct in the caller and no copy.
>
> Is this (The latter) an approach you would use? Or there is a 
> better way to do this.

You say your idea is "like passing some argument", so why not 
actually pass an argument?

For example:

     enum Direction { asc, desc }
     enum InPlace : bool { no, yes }

     ref Arr sort(ref Arr arr, Direction dir, InPlace inPlace = 
InPlace.no)
     {
         if (inPlace) {
             arr.sortInPlace(dir);
             return arr;
         } else {
             return arr.sortedCopy(dir);
         }
     }

Usage would look like this:

     auto sorted = arr.sort(asc); // sorted copy
     arr.sort(desc, InPlace.yes); // sort in place