Learning from
Ruby
Kang-min Liu <gugod@gugod.org>
YAPC::Asia::2009

Gugod->meta
• • http://handlino.com/
Kang-min Liu
gugod
• http://gugod.org
• http://search.cpan.org/
~gugod/
• http://twitter.com/gugod
• gugod@gugod.org

Learning from
Ruby

Learning from
Ruby

Ruby is Lovely
(The programming language)

Perl 6 Logo

Language

rubyisms.pm
by Simon Cozens

rubyisms.pm
• Class
• new
• self
• super
• yield

Perl ~~ Ruby

Ruby

self

class Foo
def bar
self.baz
end
def self.bar
self.baz
end
end

class Foo
def bar
object
self.baz
end
def self.bar
self.baz
end
end

class Foo
def bar
object
self.baz
end
Class def self.bar
self.baz
end
end

class Foo
def bar
baz
end
def self.bar
baz
end
end

block syntax

def foo(arg1, arg2)
yield(a, b)
end
foo(arg1, arg2) do |block_arg1, block_arg2|
...
end

co-routine

callback

call me after you
done that.

div(id => "content") do
h1(id => "title") { "OHAI" }
p(class => "block") { "Cheeze?" }
end

app do
alert(42)
end

Good Built-in
Classes

Range

Lazy

irb> 1..2**100
=>
1..1267650600228229401496703205376
irb> (1..2**100).class
=> Range

(1..2**100).each do |i|
puts 42
break if i >= 5
end

autobox

no Semicolon

Rubyish.pm
It’s all sugar, honey.

Rubyish.pm
• Kernel, Object, Module, Class
• Array, Hash, String, TrueClass,
NilClass, Enumerable
• Syntax
• def, nil, true, false

class Foo {
}

def foo {
# $self;
}

def foo($arg1, $arg2) {
}

see also:
MooseX::Declare

my $array = Array[0..3];
if ($array->any { $_ > 2 }) {
...
}

# Rubyish::Array
$arr = Array[1..10];
# Rubyish::Hash
$hash = Hash{ a => 42, b => "stuff" };
# Rubyish::String
$str = String("FooBar");

ref:
Class::Builtin

boolean
• true – TrueClass
• false - FalseClass
• nli - NilClass

sub true() {
Rubyish::TrueClass->new
}

ref:
boolean.pm
and Acme::Boolean

Hash is lazy too

fib = Hash.new { |fib, k| fib[k] = fib[k-1] + fib[k-2] }
fib[0] = 0
fib[1] = 1
puts fib[10]
# => 55

Functional
programming
-ish

Memoize
sub fib {
my $n = shift;
return $n if $n < 2;
fib($n-1) + fib($n-2);
}
memoize('fib');

Lazy stuffs
• Scalar::Lazy
• Variable::Lazy
• Scalar::Defer
• Data::Thunk

Lazy stuffs
• Tie::Array::Lazy
• Tie::Array::Lazier
• Hash + Lazy = ?

Hash::Lazy

Hash::Lazy
my $fib = Hash {
my ($h, $k)= @_;
return $h->{$k-1} + $h->{$k-2}
};
$fib->{0} = 0;
$fib->{1} = 1;
say $fib->{10}; # 55

Hash::Lazy
• export “Hash” as the constructor
• Hash::Lazy::Tie

Learnt
• I hate doing tie
• Spiffy constructors can be good
read
• Hash
• Rubyish.pm: Array, Hash, String
• Class::Builtin: OO

PerlX::MethodCall
WithBlock
Still more syntax sugar

Schwartzian
Transform
Ruby
(0..10)
.map { |i| i * 13 }
.map { |i| i % 17 }
.sort { |a,b| a <=> b }

Schwartzian
Transform
Perl5
sort { $a <=> $b }
map { $_ % 17 }
map { $_ * 13 }
(0..10)

Schwartzian
Transform autobox
Perl5, with
[0..10]
->map(sub { $_ * 13 })
->map(sub { $_ % 17 })
->sort(sub { $a <=> $b })

Schwartzian
Transform
Perl5, extended!
[0..10]->map {
$_ * 13
}->map {
$_ % 17
}->sort {
my ($a,$b) = @_;
$a <=> $b
};

Schwartzian
Transform
Perl5, extended!
[0..10]
->map { $_ * 13 }
->map { $_ % 17 }
->sort { $_[0] <=> $_[1] }

PerlX ::
MethodCallWithBlo
ck

ref
• B::OPCheck
• lineseq, pushmark, const
• B::Hooks::EndOfScope
• Devel::Declare

ref
• opcode.pl, opcode.h
• B::Concise
• B::Deparse

PerlX

Community

Last month

Sh*t happened

Taiwan

Morakot

☹

$WebSite.com

xdite

☹

DisasterTW.com

DisasterTW.com
• Forum
• Initial Coding: 1 hour*woman.

1 day later

DisasterTW.com
• Web 2.0 / Social-ish
• Multi-Function
• Mash-able

DisasterTW.com
✖
• Web 2.0 / Social-ish
• Multi-Function
• Mash-able

DisasterTW.com
• Online ASAP
• Robust (peak: 400k PV/day)
• Well-known

DisasterTW.com
• Rapid Prototyping
• Cloud Computing
• SEO / Social Network Friendly

DisasterTW.com
• Ruby on Rails
• Heroku + Panther CDN
• Good HTML / Plurk button

DisasterTW.com
• 6 heroku instances
• Thousands of tweets about
#morakot
• Total Cost: ~50 USD

People are
awesome

Tools are
awesome

Problem →

What if it was a
Jifty site?

@obra can haz
dancing

@obra can haz
dancing, naked

DisasterTW.com
• Rapid Prototyping
• Cloud Computing
• SEO / Social Network Friendly

DisasterTW.com
• Jifty
• Cloud Computing
• Good HTML / Plurk button

Heroku for Perl?

∴

Ruby is Lovely

Ruby is a
respectful friend
of Perl

Ruby programmers
are respectful friends
of Perl programmers

Thanks for Listening