This document summarizes a presentation about using Perl for Lego programming and various Perl projects. The presentation discusses Lorzy, a Scheme-like interpreter written in Perl that uses Moose and a type system. It also describes lcore, a 600 line sandbox written in Perl to safely run user-defined rules and actions for a request tracker system. Strong typing is emphasized as important for safety. Live demos and code links are provided.

1. Lorzy:
“Lego Programming”
in Perl
Chia-liang Kao <clkao@clkao.org>
YAPC::Asia 2009, Tokyo

2. 自己
介紹

3. id:clkao

4. 高
嘉良

7. 台湾
人

9. 日本語

10. 日本語
不會

12. Takesako
Inline::x86

14. Just In Time

15. Just In Time
Slides

16. Just In Time
Software!

17. no translation

19. RT:
Request Tracker

22. In Perl!

23. We Perl

25. $normal_user
☠ Perl

28. Lorzy:
Lazy, Lispy, Orz

29. • Scheme-like interpreter in Perl
• Typeful
• uses Moose & Moose type system

30. Example

31. Defining
Rules, Actions

32. (Think gmail filters)

36. (lambda (ticket transaction) <HERE>) :: Bool

38. sub { my ($ticket, $transaction) = @_; <HERE> }
# returns Bool

39. If ticket’s queue matches “Foo”

40. $ticket->queue->name eq “Foo”

41. S-Expression

42. (Str.Eq (RT::Model::Queue.name
(RT::Model::Ticket.queue ticket))
“Foo”)

44. Strongly Typed

45. (Types are Good)

53. Problem

54. $ticket->queue->name eq “Foo”

55. $ticket->queue->name eq “Foo”

56. $ticket->queue->name eq “Foo”

57. $ticket->queue->name eq “Foo”

58. ???!!!

65. Type mismatch!

71. Any function that takes
Str and returns Bool

72. Any function that takes
a and returns b

73. RT::Model::Ticket Bool

75. RT::Model::Ticket Bool

78. Any function that takes
a and returns a

79. Bool Bool

81. Bool Bool

83. Backend:
lcore

84. We want a sandbox

86. Dump database password, etc...

87. In Perl Environment

88. First attempt: ~2003
Audrey & Jesse

91. Type mismatch!

92. Second attempt: ~2008

94. lcore:
~600 lines

95. TODO

99. iTunes

100. iTunes
not?

101. iTunes

102. iTunes
and/or?

103. iTunes

104. iTunes
ArrayRef[Bool]

106. MooseX::Types::Applicative

107. map
isa => “CodeRef[CodeRef[a,b],
ArrayRef[a],
ArrayRef[b]]”

108. should be (a → Bool)

109. Load existing rules
into the UI

110. Conclusion

111. Visual
Programming
Environment

112. Sandbox for
providing
user
extensions

113. All about Types!

114. Live Demo!

115. http://github.com/bestpractical/rt/tree/lcore
http://github.com/bestpractical/lcore

116. clkao@clkao.org
Hackathon on weekend!

117. Questions?