Re: Removing the start or the end of some music

[Jim Long]

On Sat, Mar 30, 2013 at 10:48:59PM +0100, Mathieu Huiban wrote:
> Dear all,
> 
> I was looking how to easily remove some notes at the beginning or at the
> end of music.
> Thanks to the wonderful \extractMusic script (thank you Gilles !), it can
> be done with a few lines.
> 
> HTH,
> 
> Mathieu

Thank you very much for posting this.  I had not given it much
attention at the time, but last night I encountered a situation
where I realized that 'removeStart' was exactly what I needed.

If no one objects, your functions are sufficiently concise that I
would suggest folding them directly into the extractMusic.ly file
which is linked from the snippet URL, if the original author agrees.

Jim

> %%%
> 
> \version "2.16.1"
> \include "extractMusic.ly"  %% See  http://lsr.dsi.unimi.it/LSR/Item?id=542
> 
> removeStart = #(define-music-function (parser location music remove)
> (ly:music? ly:music?)
> "Remove, at the start of `music, a length equal to the one of `remove."
>  #{ \extractMusic $music $remove \mmR #} )
> 
> removeEnd = #(define-music-function (parser location music remove)
>       (ly:music? ly:music?)
>       "Remove, at the end of `music, a length equal to the one of `remove."
> 
>       (let*
>        ((new-length (ly:moment-sub (ly:music-length music) (ly:music-length
> remove)))
>  (newskip (make-music 'SkipEvent 'duration (make-duration-of-length
> new-length))))
>        #{ \extractMusic $music <> $newskip #} ))
> 
> 
> music = \relative { c4 c g' g a a g2 }
> 
> <<
>   \music
>   \removeStart \music s2
>   \removeEnd \music s2
> >>
> 
> %%%