On Jun 23, 2010, at 1:50 PM, Martin Drautzburg wrote:

I said that a rhythm is a series of Moments (or Beats), each expressed as
fractions of a bar. But each Moment also has volume. So I could model rhythm
as Pairs of (Moment, Volume). However I certanly do not want to specify both
the Moments and the Volume, but rather compute one from the other.

How about something like:

type RhythmScheme = [(Maybe Moment, Maybe Volume)]

type Rhythm = [(Moment, Volume)]

-- The resolution function will then be a function with type:

rhythm_from_scheme :: RhythmScheme -> Rhythm

-- Though you might want something like

-- rhythm_from_scheme :: RhythmScheme -> IO Rhythm

-- or

-- rhythm_from_scheme :: Seed -> RhythmScheme -> Rhythm

-- so that you can get and use random numbers, for example.

I guess the point of my suggestion is to let pattern matching in function definitions deal with unification of constraints. Beta reduction and unification are two sides of a coin.