1

2 define-method (d=[Directory: _] nonUnderscoreFolders) (

3 filter: d folders by: [x=_: (x name beginsWith: '_') not]

4 );;

5

6 "filter: folders d by: [$x: not (name x beginsWith: '_')]"

7

8 define [

9 Log: [indentLevel: 0 ref]

10

11 ([indentLevel: i] indentDuring: blk):

12 ( i set: i get + 1,

13 blk $ (),

14 i set: i get - 1 )

15

16 (write $x)

17 ];;

18

19 "

20 Syntactic sugar:

21

22 a + b ==> (0: a #(+): b)

23 a b ==> (#b: a)

24 a: b ==> (a: b)

25

26 [a + b] ==> [0: a #(+): b]

27 [a b] ==> [#b: a]

28 [a: b] ==> [a: b]

29 "

30

31 "

32 Read '<==>' as 'matched against' (with pattern on left, value on right)

33

34 As a pattern: ((indentLevel: i) indentDuring: blk) <==> msg

35 Expands to: (0: (indentLevel: i) indentDuring: blk) <==> msg

36 Which results in (indentLevel: i) <==> (msg $ #0)

37 and blk <==> (msg $ #indentDuring)

38 Which results in i <==> (msg $ #0) $ #indentLevel

39 and blk <==> (msg $ #indentDuring)

40

41

42 (foo: bar): ... -> bar bound to (msg $ #foo)

43 (foo bar): ... -> foo bound to (msg $ #bar)

44 (foo $ bar): ... -> illegal pattern

45 foo: ... -> foo bound to msg

46 123: ... -> 123 matched with msg

47 #foo: ... -> #foo matched with msg

48

49 Essentially, on the left of the colon (i.e. in pattern context), it is

50 a form entirely analogous to an expression, although obviously

51 application can't be matched since it's already been reduced. On the

52 right of the colon is another pattern. (??????????????????????????)

53

54 [

55 (foo: bar): zot

56

57 [foo: bar]: zot

58 ] $ msg

59

60 2 = [lowBit: false high: [lowBit: true high: zero]]

61

62 [lowBit: false high: [lowBit: true high: zero]] <>

63 [lowBit: false high: [lowBit: true high: zero]]

64 --> (false <> ([lowBit: false high: [lowBit: true high: zero]] $ #lowBit)) ^

65 ([lowBit: true high: zero] <> ([lowBit: false high: [lowBit: true high: zero]] $ #high))

66

67 ([lowBit: false high: [lowBit: true high: zero]] $ #lowBit)

68 --> {presume matching against #high fails}

69 results in false

70

71 What's the base case of the recursion??

72 Need a distinction somewhere!

73 "