Re: Simple Case Study in Types. Chords.

[Richard D Riehle <laoXhai@ix.netcom.com>]

In article <x7vogcpowyx.fsf@pogner.demon.co.uk>,
	Simon Wright <simon@pogner.demon.co.uk> wrote:

>  -- Assuming that no Chord ever spans more than an octave, we can
>  -- represent a Chord by indicating the Notes present in it
>  type Chord is array (Twelve_Tone) of Boolean;

This works fine for an equal-tempered scale such as that on a
pianoforte or fretted string instrument.  One of the beauties of
the violin family is the ability to play the subtle difference
between, say, an  G Sharp and an A Flat.  Of course, most of us
are accustomed to thinking that the sharp form of one note exactly
corresponds to the flat form of the next ascending note, so the
distinction is often unimportant.  There is also the problem of
Asian tones, some of which are slightly off from the Pythagorean
model.  

Richard Riehle