Fix #687: Include MIDI swing script in default distribution (issue 572520044 by address@hidden)

[thomasmorley65]

Hi Valentin,

up to now I didn't test, but read the code only.
Several small suggestions:


https://codereview.appspot.com/572520044/diff/574520044/ly/swing.ly
File ly/swing.ly (right):

https://codereview.appspot.com/572520044/diff/574520044/ly/swing.ly#newcode99
ly/swing.ly:99: (fold (lambda (x y) (and x y)) #t (map rational? lst))))
Why not
(every rational? lst)
?

https://codereview.appspot.com/572520044/diff/574520044/ly/swing.ly#newcode102
ly/swing.ly:102: (if (< n 1) '() (append (integers-from-1-to (1- n))
(list n))))
Why not
(iota n 1 1)
?

https://codereview.appspot.com/572520044/diff/574520044/ly/swing.ly#newcode112
ly/swing.ly:112: (ly:duration? (ly:music-property music 'duration))))
Mmh, strange check

https://codereview.appspot.com/572520044/diff/574520044/ly/swing.ly#newcode119
ly/swing.ly:119: (factr (ly:make-moment (+ 1 (/ delta dur)))))
Why not
(1+ (/ delta dur))
?

https://codereview.appspot.com/572520044/diff/574520044/ly/swing.ly#newcode163
ly/swing.ly:163: (#t
(else

https://codereview.appspot.com/572520044/diff/574520044/ly/swing.ly#newcode229
ly/swing.ly:229: (integers-from-1-to (- n 1))))
(1- n)

https://codereview.appspot.com/572520044/