Re: [Lilypond-auto] Issue 2072 in lilypond: Add proper complex variables to Lilypond

[lilypond]

Updates:
        Labels: -Bounty

Comment #5 on issue 2072 by address@hidden: Add proper complex variables to  
Lilypond
http://code.google.com/p/lilypond/issues/detail?id=2072

Ok, I have created some sketch implementation for this, basically allowing  
the function stored inside of a music function and accessed by  
ly:music-function-extract to be a procedure with setter.  There are  
syntactical ambiguities with octave checks, with \tempo, and a timing  
problem with music in output definitions.  But the main stumbling block is  
that using such a construct means that it must be strongly typed.  It is  
possible to have a vector of music variables, but you need your own  
defining command with it, and you can't just replace _some_ of those music  
variables with another vector or data structure, so things like
movement2 in parallel to movement3a and movement3b don't work out.  So this  
construct will be reasonably useful only once we can get rid of rigid  
typing for music functions: if the syntactic class of a music function does  
not need to get hardwired into the function, and Scheme, music and event  
functions are all identical to the parser, this concept has a reasonable  
chance to work in a reasonably natural manner.

That's a long-term perspective I _am_ working on in the parser, but it is  
not going to be finished by tomorrow or next week.