So what I learned is that when I call a variable on an object e.g.
my_object.variable
A method called variable is returning the value of variable
def variable
@variable
end
In Java, there are access modifiers. How can Ruby make use of access modifiers if getter methods are named after their variables?
First, there is a bit of terminology to clean up in the question before answering it.
One is that you never "call" variables. The Ruby expression
my_object.variable
is a method call. There is no such thing as a variable call. You call methods, not variables. Even if the method is named variable. :)
The second is if you did define the method like this
def variable
@variable
end
either directly or by saying
attr_reader :variable
Then you have a method named variable and a variable named @variable.
Now to answer the question.
Ruby places access modifiers public, protected, and private on methods only, and not on variables. Access controls on variables don't really make sense, because they only be referenced within an object’s methods, and never with a prefix! In other words, you can never write this:
obj.@var
That's just a syntax error. You can write
obj.var
where var is the name of a method. And the access controls apply to that method only.
The fact that you may be making variables and methods with the same name (except for the @) actually doesn't matter. Only methods have access controls.
Hope that helps clear up some understandable confusion!
my_object.variable? I understand why I cannot in Ruby.
There are several ways to make a method private in Ruby.
Use private to make all later methods private:
class Foo
def public_method
end
private
def private_method
end
end
Or make a method private after you defined it:
class Foo
def public_method
end
private :public_method # public_method is now private
end
Or - since the method definition returns a symbol too - this also works:
class Foo
private def method_name
end
end
