anchor.diff:     #:legato
      #:sustain
      #:delta
  -   #:timing-offset
   
      #:freq
      #:midinote
  
positive.code: 
     #:dur-time
     #:time-dur
     #:delta-dur
     #:dur-delta
  
     #:midinote-freq
     #:freq-midinote
  
negative.code:    #:remove-event-value
  
     #:instrument
  
     #:amp
     #:db
  