After struggling with irregular bars, I've been working on a Python3 tool that transforms a spec such as:
{
"title" : "Thema allegro",
"composer" : "Ludwig van Beethoven (1808 -1854)",
"tagline" : "J. Menu - September 2013",
"enteredby" : "Jacques Menu",
"instrumentName" : "Bassoon",
"clef" : "bass",
"key" : "g \\major",
"time" : "2/4",
"initialUpBeat" : "8*1",
"firstBarNumber" : 129,
"lastBarNumber" : 150,
"finalBarPosition" : "150:4/8",
"barNumbersAtBeginningOflines" : [135, 142, 146],
"tempoMarks" : { "129:1/8":"Thema allegro", "144:1/8":"Coda"},
"repeats" : [{"128:4/8-136:3/8", 1, []}, {"136:4/8-144:3/8", 2, ["144:1/8-144:3/8", "144:1/8-144:4/8"]}],
"partName" : "bassoonPart"
}
into a ready-to-compile Lilypond source file.
The latter contains either actual notes (all the same pitch) to check the layout, or lines merely containing the "%nnn" comment at the end, ready to be filled with the actual notes by whichever means.
The spec is in JSON format, which avoids writing a specific parser.
"136:4/8-144:3/8" denotes a range starting at the 4th eight in measure 136 and ending at the 4rd eight in measure 144, inclusive.
There are still issues regarding the description of alternatives, as you can see.
barNumbersAtBeginningOflines can be used optionally to force line breaks, to help check the score comparing it with the original.
There's also the possibility to specify doubleBarsPositions.
The score described by the spec above is part of Beethoven's Trio X WoO37 for flute, bassoon and piano:
The same skeleton could be used for the other instruments, of course.
Also, entering the spec data could be done in a GUI window as an extension.
Do you think there could be interest in such a tool for anyone else than its author?
JM