My presentation at #dyncon.

1. Hackers and Rockstars
Live programming Music in Clojure
John Vlachoyiannis
@jonromero
jon@sfalma.com
Http://mad.emotionull.com

2. Who am I?

3. Jon Vlachoyiannis
Software Samurai and Serial Entrepreneur
Teaching Parallel Processing [Greece]
Founder: Sfalma.com
Founder: busyFounder.com
Hacker: Niobiumlabs.com
http://www.linkedin.com/in/johnvlachoyiannis

4. Hackers

6. Not really

7. Hackers = Creators

10. Rockstars

11. > (equals? programming making-music)
true

12. > (equals? music is-data true)
true

13. Notes are data and code

15. Supercollider

16. { [SinOsc.ar(440, 0, 0.2), SinOsc.ar(442, 0,
0.2)] }.play;

17. Chuck

18. // make our patch
SinOsc s => dac;
// time-loop, in which the osc's frequency is
changed every 100 ms
while( true ) {
100::ms => now;
Std.rand2f(30.0, 1000.0) => s.freq;
}

19. Impromptu

20. ; make sure that everything is disconnected
(au:clear-graph)
; setup simple au graph
; piano -> output
(define piano (au:make-node "aumu" "dls "
"appl"))
(au:connect-node piano 0 *au:output-node* 0)
(au:update-graph)
; play note on piano
(play-note (now) piano 60 80 (* 1.0 *second*))

21. Toplap.org
Temporary Organisation for the Proliferation of Live Artistic
Programming

22. I can do it better!

23. Python

24. musik:> [a [ [v a d] [e [f a] ] g] [f g] [a b f [ [d s] f] f a
a] ]
musik:> [kaboosh bam [dam vd [vd a]]]
musik:>[ k+s [ k k ] s s [ k+a ] ]

25. Time (duration) is written like in real music
●
● Easy to understand
● Hand-made REPL

26. # Thanks Darth Eru for the original version!
def parse(self, origString):
root = ""
tokens = re.compile(r'([?]? ?)')
origString = [word.strip() for word in tokens.split(origString) if word.strip() != '' ]
stack = []
for element in origString:
if element[0] == '[':
if element[1:] == "":
newLevel = []
else:
newLevel = [ element[1:] ]
stack.append(newLevel)
elif element[-1] == ']':
if element[0:-1] != "":
stack[-1].append(element[0:-1])
finished = stack.pop()
if len(stack):
stack[-1].append(finished)
elif element[0]:
root = finished
else:
stack[-1].append(element)
return root

27. ● This bracket syntax is HARD
● Not so easy to add effects
● Concurrency bye-bye

28. Something “feels” wrong

29. Meet Clojure

30. What is Clojure?

31. Ok, what is Lisp?

32. “Lisp is worth learning for the profound
enlightenment experience you will have
when you finally get it; that experience will
make you a better programmer for the rest
of your days, even if you never actually use
Lisp itself a lot."
Eric S. Raymond, "How to Become a
Hacker".

33. “LISP stands for: Lots of Insane Stupid
Parentheses”
Anonymous

34. The Truth about Lisp

35. LISt Processing
LIS
● Second oldest high-level language (first is
Fortran)
● Code as Data (Homoiconic)
● Perfect for Domain-specific languages
(DSL)
● Exploratory programming

36. Clojure
● Lisp in JVM
● Concurrent programming
● Dynamic Development (REPL)
● Lazy sequences
● No side effects (almost)

37. clojure might be a better
java than java

38. public class StringUtils {
public static boolean isBlank(String str) {
int strLen;
if (str == null || (strLen = str.length()) == 0) {
return true;
}
for (int i = 0; i < strLen; i++) {
if ((Character.isWhitespace(str.charAt(i)) ==
false)) {
return false;
}
}
return true;
}
}

39. public class StringUtils {
public isBlank(str) {
if (str == null || (strLen = str.length()) == 0) {
return true;
}
for (i = 0; i < strLen; i++) {
if ((Character.isWhitespace(str.charAt(i)) ==
false)) {
return false;
}
}
return true;
}
}

40. public isBlank(str) {
if (str == null || (strLen = str.length()) == 0) {
return true;
}
for (i = 0; i < strLen; i++) {
if ((Character.isWhitespace(str.charAt(i)) == false))
return false;
}
}
return true;
}

41. public isBlank(str) {
if (str == null || (strLen = str.length()) == 0) {
return true;
}
every (ch in str) {
Character.isWhitespace(ch);
}
return true;
}

42. public isBlank(str) {
every (ch in str) {
Character.isWhitespace(ch);
}
}

43. (defn blank? [s]
(every? #(Character/isWhitespace %) s))

44. Everything is code

45. (println "Hello World")
function argument

46. Everything is data

47. (println "Hello World")
list
symbol string

48. Where is the correlation?

49. Let's get M.A.D!

50. ● Live programming (REPL)
● Using Processing (processing.org)
● Easy to extend
● Easy to understand
● Fun!

51. > (p (pattern [kick]))
;; 1/1 is kick

52. (defsample “kick” path-of-sample)
;; create as sample kick

53. (defnote A#4 @*sine*)
;; create a note

54. (create-notes)
;; creates all defnotes for notes
;; helping function

55. Everything is one data structure

56. (defrecord Melement [volume pitch duration play-
fn data])

57. play-fn can be anything you like

58. (defn play-sample [sample]
(.trigger (:data sample)))
;; for samples

59. > (p (pattern [kick]))
;; 1/1 is kick

60. pattern calculates the correct timing
updates the :duration for notes

61. > (p (pattern [kick kick]))
;; play two kicks
;; ½ kick
;; ½ kick

62. p plays each note at the correct timing

63. (p (pattern [kick (+snare hihat)]))
;; two times again
;; ½ kick
;; ½ snare with hihat

64. (p (pattern [kick [snare snare snare]]))
;; two times again
;; ½ kick
;; (½ / 3) snare
;; (½ / 3) snare
;; (½ / 3) snare

65. Just like real music

66. Now fun!
Hint: transformations

67. (p (pattern [A4 B4 C5 D5 E5 F5 G5]))

68. (p (reverse (pattern [A4 B4 C5 D5 E5 F5 G5])))

69. (p (map #(assoc % :pitch
(.nextInt (java.util.Random.) 1100))
(pattern [E4 G4 B4 E5 B4 G4]))

70. You can manipulate music as a data structure

71. (keep-looping)

72. (play! [[E4 G4 E4]
[E5 B4 G4 D4 A4 E4 G4 A4]])

73. play! Lets you experiment in real time
Live programming

74. Using Processing for Visual effects

76. Limit? The audio sky!

77. (play! (text-to-notes (get-latest-twits))
;; add markov-chains

78. Searching for members for
Band of Emacs
Give me a twit at @jonromero if interested

79. Thanks! Questions?
jon@sfalma.com
Get it at mad.emotionull.com