bindig example

binding.rb

class Demo
  def initialize(n)
    @secret = n
  end

  def get_binding
    return binding()
  end
end

k1 = Demo.new(99)
b1 = k1.get_binding
k2 = Demo.new(-3)
b2 = k2.get_binding

eval("@secret", b1)
eval("@secret", b2)
eval("@secret")

erb_exam.rb

require 'erb'
class ErbTest
  def initialize
    @last_name = 'lee'
    @first_name = 'kyle'
    @erb = ERB.new(File.read('erb_template.erb'))
  end
  attr_accessor :last_name, :first_name
  
  def to_s
    @erb.result(binding)
  end
  
  def full_name(space)
    first_name + space + last_name
  end
end

erb_test = ErbTest.new
puts erb_test.to_s

erb_exam2.rb

require 'erb'
class ErbTest
  def initialize
    @last_name = 'lee'
    @first_name = 'kyle'
  end
  attr_accessor :last_name, :first_name

  extend ERB::DefMethod
  def_erb_method('to_s', 'erb_template.erb')

  def full_name(space)
    first_name + space + last_name
  end
end

erb_test = ErbTest.new
puts erb_test.to_s

erb_template.erb

Hi <%= last_name %>
<%= first_name %>
<%= full_name(" ") %>