Basic introduction to programming concepts using Processing. Developed for code4lib 2010 conference preconf "Hacker 101/102".

1. hacker
101/102
code4lib 2010 preconference
Asheville, NC, USA 2010-02-21

2. i. intro
why are we here?

3. learn to hack?

4. ...not exactly

5. we work in libraries
so we can
help people

6. we hack
to help ourselves
help others

7. what’s a good hacker?

8. languages?
standards?
jargon?
math?
logic?
frameworks?

9. nope!

10. a good hacker
knows
when to ask for help

11. a good hacker
knows
how to ask for help

12. a good hacker
knows how
to help other hackers

13. a good hacker
knows other hackers
to ask for help

14. when to ask
how to ask
how to answer
whom to ask

15. i’m here
because i want
to be able to ask you

16. when to ask?

17. thirty minute rule

18. for today:
three minute rule

19. how to ask?
see “How to ask
questions the smart way”

20. we’ll get started
together

21. basics in Processing
regexes in JavaScript
glue it together in Python

22. explore on your own

23. get comfortable
asking for help

24. ii. the basics
Processing

25. canvas, grid, points

26. 200 300
200
400

27. lines, rects, ellipses

28. start
end

29. syntax, functions, errors

30. don’t be afraid
to break stuff

31. variables, loops

32. test
type “integer”
initial value increment
repeating
actions

33. every lang has loops
• for (a=blah, a<foo, a=a+bar) {...}
• for each (foo in blah) {...}
• for i in range(20): ...
• while (foo != bar) do {...}
• next, continue, break

34. more variables, loops

35. even more variables, loops

36. explore on your own

37. iii. functions, objects,
the main loop

38. why functions?

39. setup, draw, void

40. function structure
RETURN_TYPE FUNCTION_NAME ([var a, ...])
{...statements...}

41. setup, draw
• void: returns nothing
(into the void!)
• setup: prep stuff
• draw: the “animation
loop” or “main”

42. different kinds of “main”
• Processing: draw() is like an
animation “cell”
• in a GUI: the user feedback loop
• command-line app: parse args,
then main()
• web app: the user feedback loop

43. setup, draw, void

44. we can
write this better

45. setup, draw, void

46. see the problem?

47. setup, draw, void

48. DRY
Don’t Repeat Yourself

49. a little
better

50. more
task
specific

51. add
delay
(10);

52. initialization
now
try this
no loop!
if/else
i.e.
“conditional”

53. • draw() is already a loop;
why another?
• “i” becomes state
• tightens up draw()

54. what about objects?

55. obj
ect
i
fied

56. • it says what it is
• it removes a lot of
repeated noise
•it’s kinda overkill here
• we don’t use rp1 and rp2
again

57. no single answer
• design a matter of taste
• sometimes things should
be called what they mean
• sometimes an “int i” is
just an “int i”
• think about what you’ll
understand later

58. explore on your own