I'm looking for a music-playing program that supports nested playlists. In other words, a playlist can contain not just songs but also other playlists. Is there one around?

A bit of context: this is just what I need for playing my classical music collection. The playlist for a symphony, for instance, would be composed of individual songs (the movements); a playlist for several symphonies would be composed of the playlists for each of them. And a playlist for all the Brahms symphonies would consist of the playlists for each of the symphonies.

Generally, popular music is adequately supported by the song/album structure, but classical music isn't.

I do not use man players and know of none that do what you want.

I DO run a music server based upon streamsicle that allows EXACTLY that kind of structure. You can have a folder of music files, and subfolders of music and additional folders below that.

There are limitations, and I am not sure if they would deselect this kind of solution.
When you select music to actually play, you must select the mp3 files themselves. You can select all of them in a folder, but you cannot select all of them in a tree of folders.
Play is over the network, though nothing stops the server and player from being on the same machine.
Play is to any and all players that request from the server, but all get the same current playlist. (AND each can, using a standard browser interface, select music to add to the current list.) While they all play the same list, they may not be in sync (so you cannot use multiple laptops as speakers to cover a large lecture space, for example).

I suspect that there are other server options that may provide different features.
I will be watching this thread to see if there are any players that provide a better solution. I can think of several projects that might benefit.

Unfortunately the limitation on playing everything in the tree makes this solution not really applicable for me. I assume that your music server can handle flac files as well as mp3s. I ripped my CD collection to mp3s, only to discover that the fidelity was really not satisfactory -- and I'm not all that fussy.

I haven't investigated what form programs like Amarok use for their playlists. If I can't find a program that handles trees of playlists, I might try writing a program that takes a tree of playlists and enumerates the leaves of the tree in the form of another playlist, with a catalog of such trees. Actually playing the list would be left for something like Amarok. But that's a significant job.

I've been mulling over this challenge for quite a while, and I think I have an idea at last about a satisfactory way to organize my classical music collection. First, I'll use k3b to build a flat file of "albums", an album being the contents of a single CD. That's easy to do with k3b, and it preserves the order of tracks within a CD. Then, above that, I'll build a hierarchy of symlinks. I discovered that if you point Amarok at a directory, it will play all the leaves of that directory, in the same order that they would be listed by, say, ls.

So suppose that I have a CD with two Mozart symphonies, each consisting of several tracks. k3b will, by default, prepend the track number to the files it creates, so the order of movements is preserved. I construct a directory for each symphony whose contents are symlinks to the movements. I can then make a playlist of symphonies, where the entire symphonies themselves are played in whatever order I choose -- it need not be the order in which they appear on the CD. Placing one of those symphony directories on the playlist causes its movements to be played in the correct order.

For a composition that's spread over several CDs, such as Handel's Messiah, I can create another level of hierarchy. The 1 directory contains symlinks to the songs on the first CD, etc. Another directory, Messiah (within the Handel directory) contains 1, 2, 3 (or 01, 02, 03 if there had been more than 9). So putting Messiah on a playlist will in one step cause the entire work to be played in the correct order.

I'm still playing around with this approach -- comments and suggestions are welcome.