Learning From Ruby (Yapc Asia)

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

Ruby is Lovely
(The programming language)

rubyisms.pm

• Class
• new
• self
• super
• yield

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

def foo(arg1, arg2)
yield(a, b)
end

foo(arg1, arg2) do |block_arg1, block_arg2|
...
end

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

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

Rubyish.pm
It’s all sugar, honey.

Rubyish.pm

• Kernel, Object, Module, Class
• Array, Hash, String, TrueClass,
NilClass, Enumerable

• Syntax
• def, nil, true, false

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");

boolean

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

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

ref:
boolean.pm
and Acme::Boolean

fib = Hash.new { |fib, k| fib[k] = fib[k-1] + fib[k-2] }
fib[0] = 0
fib[1] = 1

puts fib[10]
# => 55

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
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] }

ref

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

ref

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

DisasterTW.com

• Forum
• Initial Coding: 1 hour*woman.

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

DisasterTW.com

• Jifty
• Cloud Computing
• Good HTML / Plurk button

Ruby is a
respectful friend
of Perl

Ruby programmers
are respectful friends
of Perl programmers

Learning From Ruby (Yapc Asia)

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