Re: command line lilypond, midi to stdout

[Bob Harris]

I wrote:
> > I was hoping to combine lilypond with this on the command
> > line like this:
> >    cat mysong.ly | lilypond - | velchanger | mysong.midi
> > Anybody have any ideas how I can accomplish that in a single
> > command?  My cycle is
> > edit,convert-to-midi,listen-in-garage-band, and I'm trying
> > to get it down to as few steps as possible to go from the
> > edit to hearing it

and Graham Percival replied
> Write a shell script:
>
> ----- songtomidi.sh
> #!/bin/sh
> FILE="$(basename -s ly $1 )"
>
> lilypond ${FILE}.ly
> velchanger ${FILE}.midi
> ... etc

Thanks, Graham,

I'm a little embarrassed that I didn't think to do that.  That will
solve the problem.

Pondering.... The lilypond doc (for 2.8.8) suggests that there are
certain extensions a user can make by including some scheme code in
her .ly file (at least that's my understanding of what I read).  Is
control of midi note velocity something I could accomplish that way?
I have snooped through the lilypond source code (2.9.29) and I see all
notes have velocity=127 (called dynamic_byte_) assigned in the
constructor and it appears they are never altered.  But I wonder if
note objects are something I can modify using a scheme extension.  Is
it possible?  Are there examples of what sort things can be done with
extensions?

Bob H