Re: Issue 2376 in lilypond: Automatic footnotes on \null markups causes unexpected results

[lilypond]

Comment #6 on issue 2376 by address@hidden: Automatic footnotes on \null  
markups causes unexpected results
http://code.google.com/p/lilypond/issues/detail?id=2376

A whole note stencil has properties.  A non-empty list has elements, a  
non-empty string has characters.  Those can be changed and overwritten.   
For that reason, you need to create copies before you modify something  
like '(a) or "a", or things may go wrong.  But you don't need to create  
copies before working with '() or "" since there is nothing that could be  
modified here.  They are self-contained.  It would be nice if we had an  
elemental entity satisfying ly:stencil? that had the same property of being  
a basic extensible building block without repercussions on the original.

There will be lots of situations where one will want to pass a typed  
equivalent of "nothing", and it is a nuisance if "nothing" needs to get  
allocated anew every time and is not eq? to "nothing".