Some techniques from the heady world of Functional Programming implemented in idiomatic Perl using various techniques: closures, iterators, Devel::Declare, and some distilled evil. New version now with monads! (As presented at http://conferences.yapceurope.org/lpw2008/ )

14. A sequence cycle [2.5, 2, 2];

15. A sequence 10, cycle [2.5, 2, 2];

16. A sequence mult, 10, cycle [2.5, 2, 2];

22. A sequence mult , 10, cycle [2.5, 2, 2];

23. A sequence scan mult, 10, cycle [2.5, 2, 2];

24. (Scanning)‏ scan add, 1, [2, 3, 4]; # [1, 3, 6, 10]

25. A sequence scan mult, 10, cycle [2.5, 2, 2];

26. A sequence take 12 => scan mult, 10, cycle [2.5, 2, 2];

27. A sequence say for take 12 => scan mult, 10, cycle [2.5, 2, 2];

38. Some light relief

39. Some light relief Monads

43. Monad tutorials

44. Monad tutorials

45. Monad tutorials

46. Monad tutorials

47. Monad tutorials Step 1: Write Monad Tutorial

48. Monad tutorials Step 2: ???

49. Monad tutorials Step 3: Profit!

53. Sequencing my $x = 1; my $y = 2; my $z = $x * $y; say “$x * $y = $z”;

54. Sequencing my $x = 1; my $y = 2; my $z = $x * $y; say “$x * $y = $z”;

55. Sequencing my $x = 1; my $y = 2; my $z = $x * $y; say “$x * $y = $z”;

56. Sequencing my @seq = sub { my $x = 1 }, sub { my $y = 2 }, sub { my $z = $x * $y }, sub { say "$x * $y = $z" };

57. Sequencing my @seq = sub { my $x = 1 }, sub { my $y = 2 }, sub { my $z = $x * $y }, sub { say "$x * $y = $z" }; # Global symbol "$x" requires explicit package name at ...

58. Nesting my $x = 1; my $y = 2; my $z = $x * $y; say “$x * $y = $z”;

59. Nesting sub { my $x = 1; sub { my $y = 2; sub { my $z = $x * $y; sub { say "$x * $y = $z"; }->() }->() }->() }->();

88. Maybe $FH = open($file)‏ $line = <$FH> $val = lookup ( $line )‏ say “Found $val”

89. Maybe $FH = open($file)‏ $line = <$FH> $val = lookup ( $line )‏ say “Found $val”

90. Sequence

91. Maybe ? ? ?

92. Multiple (List)‏

93. List $x = [1..10] $y = [1..10] guard $x+$y == 10 say “$x+$y=10”