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

自己
介紹

id:clkao

高
嘉良

台湾
人

日本語

日本語
不會

Takesako
Inline::x86

Just In Time

Just In Time
Slides

Just In Time
Software!

no translation

RT:
Request Tracker

In Perl!

We Perl

$normal_user
☠ Perl

Lorzy:
Lazy, Lispy, Orz

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

Example

Defining
Rules, Actions

(Think gmail filters)

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

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

If ticket’s queue matches “Foo”

$ticket->queue->name eq “Foo”

S-Expression

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

Strongly Typed

(Types are Good)

Problem

$ticket->queue->name eq “Foo”

$ticket->queue->name eq “Foo”

$ticket->queue->name eq “Foo”

$ticket->queue->name eq “Foo”

???!!!

Type mismatch!

Any function that takes
Str and returns Bool

Any function that takes
a and returns b

RT::Model::Ticket Bool

RT::Model::Ticket Bool

Any function that takes
a and returns a

Bool Bool

Bool Bool

Backend:
lcore

We want a sandbox

Dump database password, etc...

In Perl Environment

First attempt: ~2003
Audrey & Jesse

Type mismatch!

Second attempt: ~2008

lcore:
~600 lines

TODO

iTunes

iTunes
not?

iTunes

iTunes
and/or?

iTunes

iTunes
ArrayRef[Bool]

MooseX::Types::Applicative

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

should be (a → Bool)

Load existing rules
into the UI

Conclusion

Visual
Programming
Environment

Sandbox for
providing
user
extensions

All about Types!

Live Demo!

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

clkao@clkao.org
Hackathon on weekend!

Questions?