Convert Tag -> Filename: Multiple Artists (Values)

Hello everybody!

A problem I am facing is being lazy with putting multiple artists into the filename.
It's easy with ID3v2.3, since it's one artist field where artists are seperated by a character ('/').
This character can be replaced when converting the tag into the filename.
However, with the FLAC format it's a second, third or more field:
ARTIST=Artist1
ARTIST=Artist2
...
So this required me to look around a bit more for a good way to do this.
I found the following solutions in order:

What I was doing first for ID3v2.3:

$replace(%artist%,/,' feat. ')

Then I did this for FLAC:

$replace($meta(artist),',',' feat.')

Then I tried tackling both in one:

$replace($meta(artist),',',' feat.','/',' feat. ')

As you can see, with more variants of multiple values, the solutions get longer.

So I figured out a better solution to this (my current solution):

$replace($meta_sep(artist,'/'),'/',' feat. ')

This still isn't what I'm looking for, since this is a solution for ID3v2.3 (separation character '/') and multiple tags of the same kind (which is the case with FLAC).
And that's annoying right? Having to figure out what kind of separations there are for every format. I think ID3v2.4 uses a 'NULL' to separate values, so I'm guessing that would not work with my current solution.

So is there anyone out there with a better solution?

Otherwise I'd like to suggest a new feature:

$separate_by(placeholder,string)

Example:$separate_by(%artist%,' feat. ')
Mp3tag should know how the field is separated with multiple values for every tagging format.
Then I would simply say what string I want the values to be separated with.

Hello new user DmasterD, you ask questions about the recurring theme "multi value tag" and about putting multiple artist names into the filename.
For me, the filename is the worst possible place for multiple artist names; the tagfield ARTIST is a good place.

You can find many forum entries regarding the theme "multi valued tag field" ...
https://www.google.de/search?q=site%3Amp3ta...ulti+value+tags

I recommend you to read something, and then you come back and ask specifically what you want to know additionally.

Maybe this post can help to understand ...
/t/15443/1

DD.20170914.1850.CEST