Random note generator in Ruby

readmidi.rb

require 'midilib'
require 'simple-random'
    include MIDI

def get_number
    rand(2000)
end

seq = nil unless seq.nil?
seq = Sequence.new()

track = Track.new(seq)
seq.tracks << track
track.events << Tempo.new(Tempo.bpm_to_mpq(238))
track.events << MetaEvent.new(META_SEQ_NAME, 'Rubulastic')

track = Track.new(seq)
seq.tracks << track

track.name = 'Rubulastic'
track.instrument = GM_PATCH_NAMES[0]

track.events << Controller.new(0, CC_VOLUME, 127)

track.events << ProgramChange.new(0, 1, 0)
note_length = seq.note_to_delta('32nd')

for var in 23..532
    channel = 0
    note = get_number
    velocity = get_number
    start = 0
    track.events << NoteOnEvent.new(channel, note, velocity, start)
    track.events << NoteOffEvent.new(channel, note, velocity, note_length)
    if (var%23 == 0)
        controller, data = get_number, get_number
        if (controller == CC_VOLUME)
            controller = controller + 1
        end
        track.events << Controller.new(0, controller, data)
    end
end

File.open('output.mid', 'wb') { | file | seq.write(file) }