Ruby Meetup Balabit

First steps in Ruby

March 17, [email protected]

MeetUP @ Balabit

mailto:[email protected]


Reality is just a scope of an artist...

Balabit Meetup - March 17, 2010 [email protected]




Ruby

Yukihiro Matsumoto (1995)

www.meetup.com/budapest-rb

“... They are focusing on machines. But in fact we need to focus on humans, on how humans care about doing programming or operating the application of the machines. We are the masters. They are the slaves.”



http://www.meetup.com/budapest-rb

http://www.meetup.com/budapest-rb


Lego




Objects

class Brickend

class Workerend

class Treeend

class RoofTileend




Objects

class Brickend

class Workerend

class Treeend

class RoofTileend

2




Objects

class Brickend

class Workerend

class Treeend

class RoofTileend

22.prim?2.upto 5




Objects

class Brickend

class Workerend

class Treeend

class RoofTileend

22.prim?2.upto 5nil




Objects

class Brickend

class Workerend

class Treeend

class RoofTileend

22.prim?2.upto 5nilnil.nil?




Brick objects

class Brick attr :color attr :socketsend




Yellow and Red bricks

class YellowBrick < Brick def initialize @color = :yellow # @ instance variable (always protected!) @sockets = 6 # @@ class variable endend

class RedBrick < Brick def initialize @color = :red @sockets = 6 endend




Yellow and Red bricks

class YellowBrick < Brick def initialize @color = :yellow # @ instance variable (always protected!) @sockets = 6 # @@ class variable endend

class RedBrick < Brick def initialize @color = :red @sockets = 6 endend

> yellowBrick = YellowBrick.new > redBrick = RedBrick.new

> p yellowBrick #<YellowBrick:0x10012ac68 @color=:yellow, @sockets=6>




Altering objects

class Brick attr :color attr_accessor :sockets end

attrattr_accessor




Altering objects


class Brick def color return @color end end

# return is not required!

attr

attr_accessor




Altering objects


class Brick def color return @color end end

# return is not required!

class Brick def sockets @sockets end def sockets= (value) @sockets = value end end

attr attr_accessor




Assigning

class Brick attr :color attr_writer :sockets def sockets= (number) raise Exception.new("Invalid socket number") if number % 2 != 0 raise Exception.new("Too many sockets") unless number <= 10 @sockets = number end end




Assigning

class Brick attr :color attr_writer :sockets def sockets= (number) raise Exception.new("Invalid socket number") if number % 2 != 0 raise Exception.new("Too many sockets") unless number <= 10 @sockets = number end end

> yellowBrick = YellowBrick.new > yellowBrick.sockets = 4 > puts yellowBrick.sockets # 4

> yellowBrick.sockets = 5 # Exception: Invalid socket number




Box

class Box def initialize @items = [] end

def << (item) @items << item endend




Box



> box = Box.new > > 1.upto 5 do |number| > brick = YellowBrick.new > brick.sockets = number * 2 > box << brick > end

> p box > #<Box:0x10012a650 @items=[#<YellowBrick:0x10012a498 @color=:yellow, @sockets=2>, #<YellowBrick...




Box




> p box > #<Box:0x10012a650 @items=[#<YellowBrick:0x10012a498 @color=:yellow, @sockets=2>, #<YellowBrick...

#<Box:0x10012a650 @items=[#<YellowBrick:0x10012a498 @color=:yellow, @sockets=2>, #<YellowBrick:0x10012a510 @color=:yellow, @sockets=4>, #<YellowBrick:0x10012a4c0 @color=:yellow, @sockets=6>, #<YellowBrick:0x10012a470 @color=:yellow, @sockets=8>, #<YellowBrick:0x10012a448 @color=:yellow, @sockets=10>]>




Searching

class Box def search (&block) @items.each do |item| yield item end endend




Searching

class Box def search (&block) @items.each do |item| yield item end endend


> box.search do |brick| > puts “#{brick.sockets} “ > end

# 2 4 6 8 10




How to start...

apt-get install ruby

apt-get install irb

apt-get install rubygems (11345 packages)

gem install rails gem install SyslogLogger gem install hpricot




More information...

http://www.ruby-lang.org

http://www.rubygems.org

http://TryRuby.org







http://TryRuby.org

http://TryRuby.org


2.prim?

class Integer def prim? myValue = self.to_i return false if myValue == 1

2.upto myValue-1 do | i | return false if (myValue % i) == 0 end

return true endend




2.prim?

class Integer def prim? myValue = self.to_i return false if myValue == 1

2.upto myValue-1 do | i | return false if (myValue % i) == 0 end

return true endend

Questions?




Thank you!



Ruby Meetup Balabit

Technology

Transcript of Ruby Meetup Balabit