start with classes and instances
Classes
store instance methods
have a superclass pointer
Instances
store instance variables
have a class pointer
Classes are also instances (of Class)
Method lookup
when you invoke a method on an instance
start by going to its class
until you find the method, go to the superclass
once you find it, create a scope for that object
and run the code for the method in that scope
Scopes/Bindings
all code executes in a scope
store local variables
they have a self (an instance that they are operating in)
this gives them access to instance variables
they can call methods on that object
What are C classes and objects underneath the magic? https://github.com/ruby/ruby/blob/65a5162550f58047974793cdc8067a970b2435c0/ruby.h#L218-233
class HasExtraStuff
def get_name
@name
end
def get_binding
binding
end
end
class Person < HasExtraStuff
def initialize(name)
@name = name
end
def get_initial
get_name[0]
end
end
joshs_name = "Josh"
josh = Person.new(joshs_name)
josh.get_name # => "Josh"
josh.get_initial # => "J"
josh.get_binding.eval('self') # => #<Person:0x007fe6348454f0 @name="Josh">
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