Ruby ni pure object-oriented — unafafanua classes (blueprints) na kuunda objects (instances). Classes hutumia initialize kama constructor, @variables kwa hali ya instance, na access modifiers kwa encapsulation. Sintaksia ya class ya Ruby ni safi na yenye uwazi.
class Person
def initialize(name, age) # the CONSTRUCTOR (called on .new)
@name = name # @ → instance variable (per object)
@age = age
end
def greet # an instance method
"Hi, I'm #{@name}"
end
end
person = Person.new("Ann", 30) # create an instance (calls initialize)
person.greet # "Hi, I'm Ann"
Method ya initialize ni constructor (huitwa kiotomatiki na .new), na instance variables za @name hushikilia hali ya kila-object. Methods hufafanuliwa kwa def.
class Person
attr_accessor :name # generates getter AND setter for @name
attr_reader :age # getter only (read-only)
def initialize(name, age)
@name = name
@age = age
end
end
person.name # "Ann" — getter
person.name = "Bob" # setter
Instance variables (@name) ni private kwa default — unaziweka wazi kwa accessor methods. attr_accessor/attr_reader/attr_writer huzalisha methods hizi za getter/setter kiotomatiki (urahisi wa Ruby).
class Account
def deposit(amount) # public by default
update_balance(amount)
end
private # methods below are PRIVATE
def update_balance(amount)
@balance += amount
end
def self.create # CLASS method (self.) — called on the class, not an instance
new(...)
end
end
Account.create # class method
Methods ni public kwa default; private/protected huzuia ufikiaji. def self.method inafafanua class method (huitwa kwenye class yenyewe).
Classes na objects ni za msingi kwa Ruby, ambayo ni lugha ya pure object-oriented, hivyo kuzielewa ni muhimu kwa uendelezaji wowote wa Ruby — takriban msimbo wote wa Ruby (na frameworks kama Rails) umepangwa katika classes.
Kujua jinsi ya kufafanua classes kwa initialize constructor, kutumia @instance variables kwa hali ya kila-object (na kwamba ni private kwa default, zinahitaji accessor methods kuziweka wazi), kufafanua instance na class methods (def self.method), na kutumia udhibiti wa ufikiaji (private/protected) ni maarifa ya msingi ya kila siku.
Urahisi muhimu hasa wa Ruby ni attr_accessor/attr_reader/attr_writer, ambao huzalisha methods za getter/setter kiotomatiki kwa instance variables — ukiondoa boilerplate na kuonyesha uvutio wa Ruby (badala ya kuandika getters/setters za wazi kama katika lugha nyingi, unazitangaza katika mstari mmoja).
Kuelewa sintaksia safi ya class ya Ruby, muundo wa constructor na instance-variable, accessor methods, na class methods ni maudhui ya msingi, ya lazima kujua kwa object-oriented Ruby.
Kwa kuwa classes ndivyo unavyo-model data na tabia katika programu zote za Ruby, na kwa kuwa vipengele vya class vya Ruby (desturi ya initialize, @ instance variables, attr_* accessors, udhibiti wa public/private) ndivyo object-oriented Ruby inavyoandikwa, kuvimudu ni maarifa muhimu, ya msingi yanayoshikilia uendelezaji wote wa Ruby na sehemu ya mara kwa mara ya kuanzia kwa kuelewa asili ya object-oriented ya lugha.