Re: Issue 687 in lilypond: Enhancement: inequal MIDI quantization of equal durations (swing, rubato)

[lilypond]

Comment #14 on issue 687 by chicagogrooves: Enhancement: inequal MIDI  
quantization of equal durations (swing, rubato)
http://code.google.com/p/lilypond/issues/detail?id=687

Here is a prototype scheme-based implementation which works for streams of  
notes/rests which are quarter-note length or less:

http://music.chicagogrooves.com/lilypond-swing-dev.zip

A couple of things I wish I had when doing this:

1. A way to simply add to the duration of a note - instead of needing call  
ly:compress-music with some clever ratio - I just want to add or subtract  
1/6 of a quarter note and be done with it

2. A way of iterating which tells me not just the duration of the current  
event, but the amount of time in moments since the beginning. I just  
created a few bookkeeping variables to keep track in my map-music block.

3. An understanding of why I need (begin  ) blocks and what they do..

4. A REPL for testing out scheme stuff

But I'm excited to have at least this - feedback would be very welcomed