Re: A must-see for anybody on this list

[Joseph Rushton Wakeling]

On 02/12/2013 03:05 AM, David Kastrup wrote:
> The advantage LilyPond has over the hand engraver is that it does not
> need to say "I don't make mistakes".  The hand engraver puts down the
> staff lines, and short of throwing the plate(s) away and starting over,
> the layout has to fit those lines, and the page breaks have to match
> those bars in eternity.  And "give me that transposed for Bb" is an
> inexpensive option, as well as "can you play that for me?".

That's something of a dangerous assumption.  Consider this little snippet, where 
a trill-with-accidental is included according to the instructions on 
articulations and ornamentations:
http://lilypond.org/doc/v2.16/Documentation/notation/expressive-marks-attached-to-notes#articulations-and-ornamentations

{
  \once \override Script #'script-priority = #-100
  a'\trill^\markup{ \flat }
}

i.e. an A trilling with B flat.  Now compare what comes out of a transposition 
to the key of B flat:

{
  \transpose bes c' {
    \once \override Script #'script-priority = #-100
    a'\trill^\markup{ \flat }
  }
}

... which gives you a B natural trilling with C flat, whereas you _want_ to see 
a B natural trilling with C natural.

This is a general problem of most computer notation programs, not just Lilypond 
-- friends who work extensively on film/TV scores or who do regular workshops 
with composition students in music colleges encounter these sorts of issues all 
the time.

The other very typical one is seeing things like F-flats and B-sharps scattered 
throughout an atonal score, because the automated transposition rules assume 
tonal music.

> Like with CNC-milling of violins, or the tuning of organs, the advantage
> of the craftsman is not being consistently more precise than a machine,
> but of being able to focus precision and perceived precision on those
> aspects where they really count for human observers.

Indeed, and you can extend that to things like transposition -- even without the 
mistakes in automation such as those described above, it may be convenient to 
transpose a given note or passage in a slightly different way, to make it appear 
"nicer" from the point of view of the player.