Using Ruby's Struct Class.

1. Ruby’s Struct Class
typdef struct { int id; char *name; } Awesome;
Ken Collins
metaskills.net
Monday, November 14, 11

2. A Struct is a convenient way to
bundle a number of attributes
together, using accessor
methods, without having to
write an explicit class.
Monday, November 14, 11

3. Ad Hoc Example
Language = Struct.new(:name, :class_based)
ruby = Language.new "Ruby", true
js = Language.new "JavaScript", false
objc = Language.new "Objective-C"
ruby # => #<struct Language name="Ruby", class_based=true>
js # => #<struct Language name="JavaScript", class_based=false>
ruby.class_based # => true
js.class_based # => false
objc.class_based = true
objc.class_based # => true
Monday, November 14, 11

4. Sub Class Example
class MyObject < Struct.new(:id, :name, :key)
end
o = MyObject.new # => #<struct MyObject id=nil, name=nil, key=nil>
o.id # => nil
o.name # => nil
o.id = 12345
o.name = "Test Object"
o # => #<struct MyObject id=12345, name="Test Object", key=nil>
Monday, November 14, 11

5. But Why Structs?
class MyObject
attr_accessor :id, :name, :key
def initialize(*args)
@id, @name, @key = args
end
end
o = MyObject.new 12345, "Test Object"
o.id # => 12345
o.name # => "Test Object"
Monday, November 14, 11

6. But Why Structs?
Monday, November 14, 11

7. But Why Structs?
Convenient Alternative.
Monday, November 14, 11

8. But Why Structs?
Convenient Alternative.
Attribute Methods With [] & []=
Can Be Powerful. Not ivar based.
Monday, November 14, 11

9. But Why Structs?
Convenient Alternative.
Attribute Methods With [] & []=
Can Be Powerful. Not ivar based.
Easy Enumeration Of Attribute Data.
Monday, November 14, 11

10. But Why Structs?
Convenient Alternative.
Attribute Methods With [] & []=
Can Be Powerful. Not ivar based.
Easy Enumeration Of Attribute Data.
Default Equality On All Attributes.
Monday, November 14, 11

11. Attribute Accessors
class Person < Struct.new(:name)
def name
parts = self[:name].to_s.split(' ')
capped_parts = parts.map { |x| x.capitalize }
capped_parts.join(' ')
end
end
p = Person.new "KEN coLLins"
p.name # => "Ken Collins"
p[:name] = 'mETAskiLLs'
p.name # => "Metaskills"
Monday, November 14, 11

12. Easy Enumeration
Customer = Struct.new(:name, :address, :zip)
joe = Customer.new("Joe Smith", "123 Maple, Anytown NC",
12345)
joe.each { |x| x }
# >> Joe Smith
# >> 123 Maple, Anytown NC
# >> 12345
joe.each_pair { |name, value| puts("#{name} => #{value}") }
# >> name => Joe Smith
# >> address => 123 Maple, Anytown NC
# >> zip => 12345
Monday, November 14, 11

13. Default Attribute Equality
Customer = Struct.new(:name, :address, :zip)
joe = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345)
joejr = Customer.new("Joe Smith", "123 Maple, Anytown NC", 12345)
jane = Customer.new("Jane Doe", "456 Elm, Anytown NC", 12345)
joe == joejr #=> true
joe == jane #=> false
Monday, November 14, 11

14. Thanks!
Ken Collins
metaskills.net
Monday, November 14, 11