From f7df8623b9c6277764bec3d11057c92ccaa03cee Mon Sep 17 00:00:00 2001
From: Spencer Russell <spencer.f.russell@gmail.com>
Date: Thu, 23 Jan 2014 22:30:36 -0500
Subject: [PATCH] adds lilyplay.jl, a great example script from Jiahao Chen

---
 examples/lilyplay.jl | 106 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 106 insertions(+)
 create mode 100644 examples/lilyplay.jl

diff --git a/examples/lilyplay.jl b/examples/lilyplay.jl
new file mode 100644
index 0000000..744105f
--- /dev/null
+++ b/examples/lilyplay.jl
@@ -0,0 +1,106 @@
+# Thanks to Jiahao Chen for this great example!
+
+using AudioIO
+import AudioIO.play
+
+type note{S<:Real, T<:Real}
+    pitch::S
+    duration::T
+    sustained::Bool
+end
+
+function play(A::note, samplingfreq::Real=44100, shape::Function=t->0.6sin(t)+0.2sin(2t)+.05*sin(8t))
+    timesamples=0:1/samplingfreq:(A.duration*(A.sustained ? 0.98 : 0.9))
+    v = Float64[shape(2π*A.pitch*t) for t in timesamples]
+    if !A.sustained
+        decay_length = int(length(timesamples) * 0.2)
+        v[end-decay_length:end-1] = v[end-decay_length:end-1] .* linspace(1, 0, decay_length)
+    end
+    play(v)
+    sleep(A.duration)
+end
+
+function parsevoice(melody::String; tempo=132, beatunit=4, lyrics=nothing)
+    play([0]) #Force AudioIO to initialize
+    lyrics_syllables = lyrics==nothing? nothing : split(lyrics)
+
+    note_idx = 1
+    oldduration = 4
+    for line in split(melody, '\n')
+        percent_idx = findfirst(line, '%') #Trim comment
+        percent_idx == 0 || (line = line[1:percent_idx-1])
+        for token in split(line)
+            pitch, duration, dotted, sustained =parsetoken(token)
+            duration==nothing && (duration = oldduration)
+            oldduration = duration
+            dotted && (duration *= 1.5)
+            if lyrics_syllables!=nothing && 1<=note_idx<=length(lyrics_syllables) #Print the lyrics, omitting hyphens
+                if lyrics_syllables[note_idx][end]=='-'
+                    print(lyrics_syllables[note_idx][1:end-1])
+                else
+                    print(lyrics_syllables[note_idx], ' ')
+                end
+            end
+            play(note(pitch, (beatunit/duration)*(60/tempo), sustained))
+            note_idx += 1
+        end
+        println()
+    end
+end
+
+function parsetoken(token::String, Atuning::Real=220)
+    state = :findpitch
+    pitch = 0.0
+    sustain = dotted = false
+    lengthbuf = Char[]
+    for char in token
+        if state == :findpitch
+            scale_idx = findfirst('a':'g', char) + findfirst('A':'G', char)
+            if scale_idx!=0
+                const halfsteps = [12, 14, 3, 5, 7, 8, 10]
+                pitch = Atuning*2^(halfsteps[scale_idx]/12)
+                state = :findlength
+            elseif char=='r'
+                pitch, state = 0, :findlength
+            else
+                error("unknown pitch: $char")
+            end
+        elseif state == :findlength
+            if     char == '#' ; pitch *= 2^(1/12) #sharp
+            elseif char == 'b' ; pitch /= 2^(1/12) #flat
+            elseif char == '\''; pitch *= 2        #higher octave
+            elseif char == ',' ; pitch /= 2        #lower octave
+            elseif char == '.' ; dotted = true     #dotted note
+            elseif char == '~' ; sustain = true    #tied note
+            else
+                push!(lengthbuf, char)
+                #Check for "is" and "es" suffixes for sharps and flats
+                if length(lengthbuf) >= 2
+                    if lengthbuf[end-1:end] == "is"
+                        pitch *= 2^(1/12)
+                        lengthbuf = lengthbuf[1:end-2]
+                    elseif lengthbuf[end-1:end] == "es"
+                        pitch /= 2^(1/12)
+                        lengthbuf = lengthbuf[1:end-2]
+                    end
+                end
+            end
+        end
+    end
+    #finalize length
+    lengthstr = convert(String, lengthbuf)
+    duration = isempty(lengthstr) ? nothing : parseint(lengthstr)
+    return (pitch, duration, sustain, dotted)
+end
+
+parsevoice("""
+f# f# g a a g f# e d d e f# f#~ f#8 e e2
+f#4 f# g a a g f# e d d e f# e~ e8 d d2
+e4 e f# d e f#8~ g8 f#4 d e f#8~ g f#4 e d e a,
+f#2 f#4 g a a g f# e d d e f# e~ e8 d8 d2""",
+lyrics="""
+Freu- de, schö- ner Göt- ter- fun- ken, Toch- ter aus E- li- - si- um!
+Wir be- tre- ten feu- er- trun- ken, Himm- li- sche, dein Hei- - lig- thum!
+Dei- ne Zau- ber bin den - wie- der, was die - Mo- de streng ge- theilt,
+al- le mensch- en wer- den Brü- der wo dein sanf- ter Flü- - gel weilt.
+""")