[Haskell-beginners] Re: [Haskell-cafe] music-related problem

[Serguey Zefirov]

> The thing that is hard for me to understand is how, in a functional
> paradigm, to update the entire Doc by chasing down every tie and making
> all necessary updates.

This looks like one of graph algorithms.

Notes are nodes, ties are arcs. Measures, etc are parts of node label.

soundedEnd property can be computed over this.

Actually, it would be wise to parametrize Item with computed
attributes so that you can clearly distinguish between documents where
soundedEnd is set from documents where it is not.