Understanding private methods in Ruby

Question

class Example
 private
 def example_test
  puts \'Hello\'
 end
end

e = Example.new
e.example_test

This of course will not work, because we specifi

Answer 1

The definition of private in Ruby is "can only be called without an explicit receiver". And that's why you can only call private methods without an explicit receiver. There is no other explanation.

Note that there actually is an exception to the rule: because of the ambiguity between local variables and method calls, the following will always be resolved to be an assignment to a local variable:

foo = :bar

So, what do you do if you want to call a writer called foo=? Well, you have to add an explicit receiver, because without the receiver Ruby simply won't know that you want to call the method foo= instead of assigning to the local variable foo:

self.foo = :bar

But what do you do if you want to call a private writer called foo=? You can't write self.foo = because foo= is private and thus cannot be called with an explicit receiver. Well, actually for this specific case (and this case alone), you can actually use an explicit receiver of self to call a private writer.