Re: Issue 1350 in lilypond: make convert-ly restrict to `lilypond' enviroments

[lilypond]

Comment #2 on issue 1350 by lemzwerg: make convert-ly restrict to  
`lilypond' enviroments
http://code.google.com/p/lilypond/issues/detail?id=1350

and I answered:

Unfortunately, I'm not a python guru, and handling balanced text
blocks with regular expressions is notoriously difficult.  Contrary to
Perl, which has support for that since version 5.10 (a special syntax
extension of the `+' operator and the `(?n)' construct,
cf. http://www.perlmonks.org/?node_id=660316), Python lacks this,
AFAIK.

There is the highly-praised pyparsing package, however, its license
forbids inclusion into lilypond.