Right now, there are many situations where users need to iterate over a set of files, but MC provides a limited facility for this outside of using global variables, which is beyond the abilities of most. However, there is one tool already built in that does exactly this, and with a small enhancement, it could be more useful.
This is the "Fill Track Numbers From List Order" tool.
Right now, the tool can increment only the Track # or Episode fields, and it can optionally restart at 1 only when the Album or Disc # fields change.
What I propose is making both the "Field" entry box and the "Start Over" entry box both accept typed field names. The start over box should accept a semicolon delimited list.
This would allow the user to store the count in whatever field they want, and reset the count based on whatever fields they want.
For example, if a user wanted to add Movement Numbers to their classical music, they could select a bunch of files, and invoke the tool and fill out:
Field=Movement Number
Start Over=Composition
This would populate incremental movement numbers, starting over at 1 each time the Composition field changed.
This enhancement would come in extremely handy in a variety of situations. The internal logic would stay the same (other than validating the fields entered) but the tool would be much more flexible. An example of the new dialog filled out with current defaults would look like the attached.