From: Alder Green <alder.green@...>
Date: 2006-06-30T23:33:07+09:00
Subject: Useful inconcistency in calling foo vs. foo= private methods.

Hi

This is an interesting sort of useful gotcha I recently stumbled upon:

class Foo
  private

  def bar
    p '#bar called'
  end
  def bar=(val)
    p '#bar= called'
  end
end

irb(main):002:0> foo = Foo.new
irb(main):003:0> foo.instance_eval { self.bar }
NoMethodError: private method `bar' called for #<Foo:0x2c85a68>
irb(main):004:0> foo.instance_eval { self.bar = 1 }
"#bar= called"

Formally, the the last line should have thrown an exception as well;
afaik private methods can't by definition be called with an explicit
receiver. It seems the assignment methods are exempt from this rule.
This is actually useful, since it overrides the higher precendence of
local variable assignment over method calls; if self.bar= didn't work,
I don't see any way short of self.send to call the private #bar=.

Still I thought it might be worth mentioning.

-- 
-Alder