bindingofcallerkludge.rb

require 'binding_of_caller'

# https://twitter.com/garybernhardt/status/875037876215357440

class ReallyParticularInsantiation
  def initialize
    b = binding.of_caller(1)
    # could also b.eval to get at __FILE__ and __LINENO__
    if b.eval('self.class') != Foo or b.eval('__method__') != :try
      raise RuntimeError, "I don't even know what to call this coupling"
    end
    puts 'ReallyParticularInsantiation#initalize allowed'
  end
end

class Foo
  def try
    ReallyParticularInsantiation.new
  end
end

class Bar
  def try
    ReallyParticularInsantiation.new
  end
end

def kernel_method_try
  ReallyParticularInsantiation.new
end

Foo.new.try

Bar.new.try
kernel_method_try
ReallyParticularInsantiation.new