Create a \tuplet function to complement \times and tupletSpannerDuration

ly/music-functions-init.ly

 %%%% -*- Mode: Scheme -*-
 
 %%%% This file is part of LilyPond, the GNU music typesetter.
 %%%%
 %%%% Copyright (C) 2003--2012 Han-Wen Nienhuys <hanwen@xs4all.nl>
 %%%%                          Jan Nieuwenhuizen <janneke@gnu.org>
 %%%%
 %%%% LilyPond is free software: you can redistribute it and/or modify
 %%%% it under the terms of the GNU General Public License as published by
 %%%% the Free Software Foundation, either version 3 of the License, or
@@ skipping 1323 matching lines @@
     (make-property-set 'instrumentTransposition
                        (ly:pitch-negate pitch))
     'Staff))
 
 tuplet =
 #(define-music-function (parser location ratio duration music)
    (fraction? (ly:duration?) ly:music?)
    (_i "Scale the given @var{music} to tuplets.  @var{ratio} is a
 fraction that specifies how many notes are played in place of the
 nominal value: it will be @samp{3/2} for triplets, namely three notes
 being played in place of two.  If the optional @var{duration} is

[Ian Hulin (gmail), 2013/01/11 18:28:35]

If the optional @var{duration} parameter is specified, this is used to have the
tuplet use spanner brackets differing from the total length of the music in the
tuplet. Typically this could be used to specify a group of subdivisions within
the tuplet.
For example,

 specified, it is used for initializing @code{tupletSpannerDuration}.
 For example,
 @example
-\tuplet 3/2 4 { c8 c c c c c }
+\tuplet 3/2 4 @{ c8 c c c c c @}
 @end example
 will result in two groups of three tuplets, each group lasting for a
 quarter note.  The value of @code{tupletSpannerDuration} is retained

[Ian Hulin (gmail), 2013/01/11 18:28:35]

Cut out these sentences
"The value of @code{tupletSpannerDuration} is retained as default if it is set
in this manner. Clearing it can be achieved by specifying @samp{1*0} as
@var{duration}"

 as default if it is set in this manner.  Clearing it can be achieved
 by specifying @samp{1*0} as @var{duration}.")
    (let ((scaled
           (make-music 'TimeScaledMusic
                       'element (ly:music-compress
                                 music
                                 (ly:make-moment (cdr ratio) (car ratio)))
                       'numerator (cdr ratio)
                       'denominator (car ratio)))
          (len (and duration (ly:duration-length duration))))
      (if duration
          (if (zero? (ly:moment-main len))
              #{ \unset tupletSpannerDuration
                 #scaled
              #}
              #{
                \set tupletSpannerDuration = #len
                #scaled
              #})
          scaled)))
 

[Ian Hulin (gmail), 2013/01/11 18:28:35]

Get rid of code doing things to tupletSpannerDuration.  I think this property
was a kludge they put in because you couldn't code an optional parameter when
the old \times commands was written.
Look at the NR example for tupletSpannerDuration:

{
  \set tupletSpannerDuration = #(ly:make-moment 1 4)
  \times 2/3 { c8 c c c c c }
}

WDYT?

Cheers,

Ian

 tweak =
 #(define-music-function (parser location prop value item)
    (symbol-list-or-symbol? scheme? symbol-list-or-music?)
    (_i "Add a tweak to the following @var{item}, usually music.
 Layout objects created by @var{item} get their property @var{prop}
 set to @var{value}.  If @var{prop} has the form @samp{Grob.property}, like with
 @example
 \\tweak Accidental.color #red cis'
 @end example
 an indirectly created grob (@samp{Accidental} is caused by
@@ skipping 98 matching lines @@
 Use this if you want to have a scheme expression evaluated
 because of its side-effects, but its value ignored."))
 
 withMusicProperty =
 #(define-music-function (parser location sym val music)
    (symbol? scheme? ly:music?)
    (_i "Set @var{sym} to @var{val} in @var{music}.")
 
    (set! (ly:music-property music sym) val)
    music)