Re: How does map-some-music work?

[David Kastrup]

Jay Vara <address@hidden> writes:

> I am trying to display all the names that appear in a piece of music 
> (NoteEvent etc.) using map-some-music. It the function musShow is only 
> printing the top level name. What am I missing here?
>
> %%%%%%%%%%%%%%%%%%%%
> \version "2.18.2"
> #(define (showMus music) (display-scheme-music (ly:music-property music 
> 'name "Not Defined")))
>
> musShow = #(define-music-function (parser location myx ) (ly:music?)
>             (map-some-music
>              (lambda (evt)  (showMus evt )) myx)
>             #{ #})
>
>
> music =  {c ~ c}
>
>
> \musShow #music
> %%%%%%%%%%%%%%%%%%%

The return value of map-some-music is interpreted.  Anything but #f
stops recursion.  A music expression replaces the original.  Since you
don't want to change the original music, you probably rather want
for-some-music, and then you'll still need to supply a return value
indicating whether you want to recurse or not.

-- 
David Kastrup