Code uses functions generating named args for synths, Introduced in ver 2.2dev Plays sliding chord scales and sliding Frere Jaques

SlidingChordsandFrereJaques.rb

#This piece explores the use of functions generating named args for synths
#introduced in version 2.2dev. You will need this version or later to play
#by Robin Newman Cecember 12th 2014

#The program explores the use of sliding notes in chord scales and in a rendition of Frere Jaques

use_debug false
s=0 #set s here with dummy value so that its scope is global

define :setbpm do |n| #set bpm equivalent
  s = (1.0 / 8) *(60.0/n.to_f)
end

setbpm(150)

q= 4 * s #define some note durations
c = 8 * s
m = 16 * s


define :sl do |note,slidetime=0| #set up note slide
  {note: note, note_slide: slidetime} #THIS CONSTRUCT ONLY IN v1.2.2dev ONWARDS
end

define :ncontrol do |node,pitch,slidetime,gap| #set up control and sleep gap
  control node,sl(pitch,slidetime)
  sleep gap
end

#the note() function is used several times in the next function.
#It ensures the note is a number, rather than a symbol,
#and so allows maths with it eg note(:c4)+4 => 64

define :slidescale do |startnote,duration,slideratio=0.5,major=0| #define slide scale
  #FOLLOWING LINE THIS CONSTRUCT ONLY IN v1.2.2dev ONWARDS
  env = {attack: duration*0.2,sustain: 8*duration,release: duration} #defines envelope for long scale note 
  if major==0
    sh=[2,4,5,7,9,11,12] #note shifts for major scale
  else
    sh=[2,3,5,7,8,10,12] #note shifts for minor scale
  end
  node = play startnote,env #start note
  sleep duration #sleep duration of a single scale note
  0.upto(6) do |x| #loop to slide remaining notes
    ncontrol(node,note(startnote)+sh[x],duration*slideratio,duration)
  end
  sleep 2*duration #gap before descending scale
  sh=sh.reverse[1..-1]+[0] #calc offsets for descent
  node = play note(startnote)+12,env #start note (up an octave)
  sleep duration #sleep duration of one scale note
  0.upto(6) do |x| #do note slides for scale
    ncontrol(node,note(startnote)+sh[x],duration*slideratio,duration)
  end
end

define :chordslide do |startnote,duration,slideratio| #three notes together
  in_thread do
    slidescale(startnote,duration,slideratio)
  end
  in_thread do
    slidescale(note(startnote)+4,duration,slideratio,1) #1 parameter selects from minor scale
  end
  slidescale(note(startnote)+7,duration,slideratio)
  sleep duration
end

#notes for Frere Jaques
n1=[:c4,:d4,:e4,:c4]*2 #define here to be global in scope
d1=[c]*8
n2=[:e4,:f4,:g4]*2
d2=[c,c,m]*2
n3=[:g4,:a4,:g4,:f4,:e4,:c4]*2
d3=[q,q,q,q,c,c]*2
n4=[:d4,:g3,:c4]*2
d4=[c,c,m]*2
n=n1+n2+n3+n4
d=d1+d2+d3+d4


define :playline do |n,d| #play a single line of the tune
  total=0
  d.each do |d| #calculate the total duration of the line
    total= total + d
  end
  #FOLLOWING LINE THIS CONSTRUCT ONLY IN v1.2.2dev ONWARDS
  env = {attack: q*0.2,sustain: total,release: c} #for a long slideable note of duration total

  node=play n[0],env  #start long note
  sleep d[0] #sleep for the duration of the first note in the line
  n.zip(d).each.with_index do |v,i| #now deal with sliding the remainikng notes inteh line
    if i>0 #miss out first note, already playing
      ncontrol(node,v[0],v[1]*0.3,v[1]) #slide the next note
    end
  end
end

define :frerejaques do #play all four lines in Frere Jaques
  playline(n1,d1)
  playline(n2,d2)
  playline(n3,d3)
  playline(n4,d4)
end

define :round do #set up a round
  playline(n1,d1) #play first line of first part (set to :saw)
  in_thread do #start second part using :tri
    with_synth :tri do
      frerejaques
    end
  end
  playline(n2,d2) #second line of apart 1
  in_thread do #start third part using :fm
    with_synth :fm do
      frerejaques
    end
  end
  playline(n3,d3) #third line of part 1
  in_thread do #start fourth part using :pulse
    with_synth :pulse do
      frerejaques
    end
  end
  playline(n4,d4) #last line of part 1
  sleep c*8*3 #allow last thread part to complete
end


#====================================
#now play something!
with_fx :reverb,room: 0.6,mix: 0.5 do #wrap with some reverb
  with_fx :level, amp: 0.5 do #set an overall amp: level

    use_synth :tri
    chordslide(72,0.2,0.6) #play several chord slides with differnt settings
    use_synth :fm
    chordslide(:g3,0.2,0.6)
    use_synth :prophet
    chordslide(:c4,0.4,0.5)
    use_synth :saw
    chordslide(:c2,0.5,0.8)
    use_synth :beep
    chordslide(:c6,0.1,0.3)
    sleep 0.75

    use_synth :saw
    round #play the round of FrereJaques
    sleep 1

    use_synth :pretty_bell
    chordslide(:c6,0.1,0.3) #final chordslide
  end
end