; Create an appoggiatura (grace note) on or before the current note(s)
; by Bob Crispen
; revbob@crispen.org
; 18 September 1997

(do
    (int step 1)	; step size and direction of appoggiatura
			; +ve=step up, -ve=step down

    (int ticks 10)	; duration of appoggiatura in ticks

    (int before 1)	;  1=insert appoggiatura of dur "ticks"
			;    before current beat
			; -1=put appoggiatura on current beat and
			;    shift current beat right by "ticks"

    (getInt step "How big an appoggiatura (+ve=rising)?" -127 127)
    (getInt ticks "How long an appoggiatura (ticks)?" -120 120)
    (getInt before "Before (1) or on (0) the current note?" 0 1)

    (forEachEvent
	(if (== Event.Kind NOTE)
	    (do
		(if (== before 1)
		    (do

			; Insert the appoggiatura before the current note

			(insert
			    (- Event.Time ticks)
			    Event.Chan
			    NOTE
			    (- Note.Key step)
			    Note.Vel
			    ticks
			)
		    )
		; else
		    (do

			; Shift the current note right and take off
			; the length of the appoggiatura, so it still
			; finishes at the same time it used to

			(+= Event.Time ticks)
			(-= Note.Dur ticks)


			; Stick the appoggiatura on the current beat

			(insert
			    (- Event.Time ticks) ; decrement back to orig.
			    Event.Chan
			    NOTE
			    (- Note.Key step)
			    Note.Vel
			    ticks
			)
		    )
		)
	    )
	)
    )
)