Re: Gregorian chant input in LilyPond

[Br. Samuel Springuel]

The biggest issue for this would be the fact that gabc and lilypond 
notation approach representing music from two different view points.

The different heights (a to m) in gabc represent the actual position of 
the neume on the staff, regardless of the clef position.  As a result 
"g" may correspond to fa, re, ti (or ta), so, mi, or do depending on the 
clef (c1, c2, c3 (flatted), c4, f3, or f4).  Given that Gregorian chant 
uses a movable do, this isn't as illogical as it may sound because one 
group may choose different pitches for the same neume on the same clef 
in different pieces and different groups may sing the same piece at 
different pitches.  There really is very little correspondence between a 
note's pitch and where it appears on the staff.  What matters is the 
relation between the notes (the scale) not the actual pitches.  In 
short: gabc represents the *visual representation* of a chant score 
(i.e. what appears in the manuscript), not the musical content.

Lilypond notation, on the other hand, is very much tied to the pitch. 
a' (in absolute mode) is A440 and means that regardless of key settings 
(relative mode and the transpose function both play with this mapping). 
 This makes sense because modern music (which Lilypond is designed 
around) uses a fixed do.  Regardless of who performs a piece, or which 
piece a note appears in, the same note represents the same pitch.  In 
short: lilypond notation represents the *musical content* (i.e. what we 
hear), not how it visually appears on the page (position tweaks, stencil 
tweaks, etc. excepted).

Any attempt to convert from gabc to lilypond would require bridging that 
gap by establishing conventions for how the height of a note on the 
staff maps on to a particular pitch.  That's not to say that isn't 
possible (the visual representation and the musical content are related, 
after all, otherwise scores would be meaningless), but it would require 
some thinking out and I suspect that not everyone would be satisfied 
with any particular solution.

✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝✝
Br. Samuel, OSB
(R. Padraic Springuel)

PAX ☧ ΧΡΙΣΤΟΣ