Re: Issue 824 in lilypond: Enhancement: anchors in the music stream

[lilypond]

Updates:
        Status: Started
        Owner: address@hidden

Comment #5 on issue 824 by address@hidden: Enhancement: anchors in the music  
stream
http://code.google.com/p/lilypond/issues/detail?id=824

Looking at my rather cryptic mails in the bug report, it looks like I  
should have been more explicit.  The attachment "cash.ly" contains  
definitions for the two music functions \anchor and \addAt which, given the  
desired input (copied into the end of cash.ly) produces the desired output.

The modification with map-music-function happens in-place, so one should  
preferably use this in the same manner as Scheme functions reverse!, namely  
when the result is assigned back to the source or not used otherwise  
anymore.

When this does not seem user-friendly, adding a ly:deep-music-copy call in  
the code will sort this out at the cost of memory use (typically cleared up  
by the garbage collector eventually).  A different option would be to  
open-code the part currently done by map-music-function and create copies  
only for those parts of the structure that change by \addAt.

Suggestions about where to put that code in what form?