Combine parts of tags into another

For classical music collections, I prefix each title with the capitalised surname of the composer.
I store each composer in the format "Surname, Firstname etc"

In order to do this right now, I do the following

  1. Replace TITLE with $upper(%composer%) - %title%
  2. Filename is set to %track% %title%
  3. Use Filename converter as
    OLD: %1 %2,%3 - %4
    NEW: %2 %4
  4. Split the Filename to track and title

Example: Track #3 Title "Moonlight Sonata", Composer "Beethoven, Ludwig van"

  1. TITLE -> BEETHOVEN, LUDWIG VAN - Moonlight Sonata
  2. FILENAME -> 03 BEETHOVEN, LUDWIG VAN - Moonlight Sonata
  3. Filename-> 03 BEETHOVEN Moonlight Sonata
    4.TITLE -> BEETHOVEN Moonlight Sonata

And what do you do with the different "Bachs" and "Mozarts"?

Anyway, you could use a separate tag-field (ie. selfdefined) for your short form of the composer. There is also an official tag-field called COMPOSERSORT.

That at least would it make unnecessary to mingle with the filename.
All could be done with 1 action group:

Action: Guess Values
Source: %composer%
Formatstring: %composersort%, %dummy%

Action: Format Value
Field: TITLE
Formatstring: $upper(%composersort%) - %title%

Action: Format Value
Field: _FILENAME
Formatstring: %track% %title%

Thank you

I generally do something like BACH.CPE, MOZART.L or SCARLATTI.A for the "lesser of that name".