Fomus

The first approach involves creating all the necessary objects and assembling lists, then calling FOMUS's main function to process everything. The main function is fomus and has the following format:

(fomus &key setting value ...)

setting above is one of the setting keywords listed in chapter Settings, and value is its value. Every piece of information FOMUS needs can be included in this function call. The most important settings are global, parts and events, which contain all of the part, timesig, note, rest and other objects that directly affect what appears on the score. See the individual documentation for these for an explanation of how to use them. A few examples are given below (illustrations are "raw" output processed with LilyPond version 2.4.2):

(fomus
 :output '(:lilypond :view t)
 :ensemble-type :orchestra
 :parts
 (list
  (make-part
   :name "Piano"
   :instr :piano
   :events
   (loop
    for off from 0 to 10 by 1/2
    collect (make-note :off off
               :dur (if (< off 10) 1/2 1)
               :note (+ 48 (random 25))
               :marks (when (<= (random 3) 0)
                '(:staccato)))))))
    

(fomus
 :output '(:lilypond :view t)
 :ensemble-type :orchestra
 :default-beat 1/4
 :global (list (make-timesig :off 0 :time '(3 4))
           (make-timesig :off 7 :time '(5 8)))
 :parts
 (list (make-part
    :name "Piano"
    :instr :piano
    :events
    (loop
     for basenote in '(54 42)
     nconc (loop for off = 0 then (+ off dur)
             and dur = (/ (1+ (random 4)) 2)
             while (< (+ off dur) 12)
             collect (make-note :voice '(1 2)
                    :off off
                    :dur dur
                    :note (+ basenote (random 25))))))))
    

(fomus
 :output '(:lilypond :view t)
 :ensemble-type :orchestra
 :beat-division 4
 :quartertones t
 :parts (list
     (make-part
      :partid 'flute
      :name "Flute"
      :instr :flute)
     (make-part
      :partid 'tuba
      :name "Tuba"
      :instr :tuba))
 :events (loop repeat 5
           for off = (random 1.0) then (+ off (1+ (random 1.0)))
           and dur = (random 1.0)
           and inst = (if (eq inst 'flute) 'tuba 'flute)
           collect (make-note :partid inst
                  :off off
                  :dur dur
                  :note (+ (case inst
                         (flute 72)
                         (tuba 36))
                       (/ (random 25) 2))
                  :marks (case (random 3)
                       (0 '(:accent))
                       (1 '(:staccato))))))
    

All of these settings are also present as special variables (see chapter Settings). The following example accomplishes exactly the same thing as example above:

(setf *output* '(:lilypond :view t))
(fomus
 :ensemble-type :orchestra
 :parts
 (list
  (make-part
   :name "Piano"
   :instr :piano
   :events
   (loop
    for off from 0 to 10 by 1/2
    collect (make-note :off off
               :dur (if (< off 10) 1/2 1)
               :note (+ 48 (random 25))
               :marks (when (<= (random 3) 0)
                '(:staccato)))))))
    

Specifying keywords in the fomus function always overrides what is contained in the special variables. Also, fomus accepts one additional key, :allow-other-keys. Passing a value of t to this argument allows other keys that FOMUS doesn't recognize to be present in the call. By default, fomus accepts only keywords listed in Settings.