Yeah! You can do =[Any Expression] anywhere you can edit the value of a field (so both in the Tag Action Window, or inline in the file details view). This is, of course, most useful when you can do the same operation to multiple files. Anywhere you are hand-editing things in a repetitive fashion, you can almost certainly get there quicker using the Find & Replace tool, the Fill Properties from Filename tool, or using expressions inline.
It is particularly handy for doing text manipulation. You can use all of the
String Manipulation Functions. I use RemoveLeft, RemoveRight, and Replace functions all the time to trim existing values of needless dreck.
You can, of course, reference the very field you're editing, so if you have a bunch of files that end up with this in the [Name] field:
Track04-The name of the song
Track05-The name of this song
Track06-The name of yet another songYou can get the track numbers easily enough by sorting them and doing
Fill Track Number from List Order.
But to get that needless dreck out of the [Name] field, you can select them all and do:
=RemoveLeft([Name], 8)
And, you can reference
other fields to insert their values too. You can replace the entire contents of the current field, or combine the two. Say for example you want to do the reverse of the example above, and make the [Name] field contain that annoying spaceless Track Number dash prefix? (you probably wouldn't, but just as an example):
=TrackPadNumber([Track #], 2)-[Name]
Any text you enter that isn't recognized as a Function or Field is passed through untouched. So, that becomes "Track04-The name of the song" once again.
It is handy for numbering things too. MC has a
Fill Track Numbers from List Order right-click function. But what if you want to do the same in the [Episode] field, or some other field? You can edit the [Episode] tag for a selection of files, and do:
=Counter()
MC can even do Regular Expressions, so you can get truly crazy if you're a huge nerd, and they all work for "renaming" any field inline or in the Tag AW.