'JJ Johnson', you are right. I was in a hurry this morning and the bad $meta entry has come in by autocompletition and I didn't noticed that (... should have cleaned the history lists from olde test strings and syntax failures).
I did the verification again.
Having this multi-value tag-field (extended tag view):
ARTIST=Linkin Park
ARTIST=Jay Gordon
Action: "Format Value"
Field: ARTISTSORT
Value: $meta_sep(ARTIST,'\\')
... will create a multi-value tag-field (extended tag view):
ARTISTSORT=Linkin Park
ARTISTSORT=Jay Gordon
When running ...
Action: "Format Value"
Field: ARTISTSORT
Value: $meta_sep(ARTIST,', ')
... one tag-field will be created with all values in a string:
ARTISTSORT=Linkin Park, Jay Gordon (extended tag view)
It is not possible to transport all the multi-values from one tag-field to another tag-field by a simple 'Format Value' action.
When running ...
Action: "Format Value"
Field: ARTISTSORT
Value: %ARTIST%
... one tag-field with the first value only will be created:
ARTISTSORT=Linkin Park (extended tag view)
DD.20110510.1254.CEST