Normally, if you have a private method, you can’t call it with an explicit receiver, even if that receiver is
self. So you can’t say
def foo self.bar # explicit receiver end private def bar 123 end
foo needs to call simply
bar, leaving the
def foo bar # implicit receiver end
However, when you call setters, you always need an explicit receiver, or you’ll just assign a local variable:
def assign_things self.a = 123 b = 456 end def a=(v) puts "This one gets called." end def b=(v) raise "This one never does; the other method makes a local called `b` instead." end
So, what do you do if you have a private setter? You call it with an explicit receiver:
def assign_things self.a = 123 end private def a=(v) puts "This is called successfully." end
There’s a crazy special exception in Ruby that lets you use an explicit receiver of
self with a setter just so that you can call private setters.
This strikes me as weird. Why can’t you call any private method explicitly on self? I thought it was just easier to implement Ruby if you couldn’t, but if they made it work for setters, I’m not sure what the big deal is.