Feature request: index value formatting

[ruckmann]

Dear Simon,

I am a big fan of minim server for a long while, and I highly appreciate all the nice features available to organize my large classical music collection (actually roundabout 60.000 items) in a very structured way and with little tag information redundancy.

One of the nicest features is tag formatting available for display items and for Artist as index item. However, I miss such a functionality available for item values and index values in general. Such a function would allow me to derive and to compose new index values and new item values from given ones, e.g.

- workbytitle from title, tonality, opus number, subtitle
- workbyopus from opus number, title, tonality, subtitle

Both tag values would allow to navigate through titles alternatively sorted by it's title name and alternatively sorted by opus number. It would be very helpful to have both navigation options.

I potentially see other derivations also making sense, e.g.

- composerwithlifetime derived from composer, composerlifetime

I think, all the basic functionality needed to provide such a functionality is already in (tag formatting). I would highly appreciate if you could manage to provide such an extended and general tag formatting functionality as part of a new release.

If you need more information about my ideas or my request or if you want to discuss my request, please let me know.