Woah, so many questions! Great to see the concepts sparking some interest :D
So this would mean that Flows are not nestable, correct?
OK: Let's say I have a larger work, already organized in Flows on the movement level. Now I want to make a suite from this piece, linking several shorter passages together in new order. [begging the question: can I have more than one "full score" within one file?] If I understand Paul correctly, I cannot pull them out as Flows from the movement, since the movement is the Flow already. But could I define new Flows (on the same level as the movements), encompassing the relevant passages, and then arrange those Flows into something new? Basically: Can something be part of several flows, just as players can be common to several Flows?
You are correct in that the content from one Flow can't be recombined into another (aside from copy & paste). Each Flow owns the music within it (however, at the lowest level we store these as blocks, which may provide a means of having 'linked copies' at some point in the future, but they still have to be owned by a single Flow).
Is a Flow necessarily linked to concrete timings? I see how that would be almost unavoidable for anything within one Flow; if it is built from notes and rests it has to have durations (but I could imagine interesting cases where these are strictly relational, without a tempo). However, can two Flows exist within the same file and have no temporal relation towards each other? Or does each flow have a defined start and end moment defined in clock time?
Each Flow is thought to be a single 'piece' of music that is generally assumed to be displayed and played back from start to end. However, where there's more than one Flow we hope to give some control as to how you would want these to be played back - eg play back in Flow order with a 2 bar gap between each, omitting Flow 3 because that's an Ossia. It should be quite flexible.
Also, can I reuse Flows or will they always be single instances? Taking Paul's example of using very short Flows for explanatory purposes: Can I compile a exhaustive collection of snippets to explain extended techniques notation at the start of a score and then, at the start of a new movement, compile a smaller list reusing just the notations relevant to the movement?
Yes, I think so, because there is an additional concept: Music Frames (caveat: this is the development name, I don't know whether that will be the user-facing name). Flows define the content, and Music Frames define how that is to be presented on the page. Music 'flows' through a sequence of Music Frames until it runs out, then it will move on to the next Flow. You can create a new sequence of music frames if you want to reuse the content from a Flow.
Which makes me think what the more suitable way for the understanding of Flows might be: is the Flow concept predominantly a solution to problems of music modelling or to problems in laying out materials?
It's very similar to the concepts of a DTP application, though I'm not sure if they use the same names. In short:
- Flow = a section of musical content
- Music Frame = a box on a page through which music is to be 'flowed', in sequence
- Layout = a visual presentation of a combination of Flows and Players, displayed using a particular page layout. Think: 'Parts'
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