class Binding

Public Instance Methods

irb() click to toggle source

Opens an IRB session where binding.irb is called which allows for interactive debugging. You can call any methods or variables available in the current scope, and mutate state if you need to.

Given a Ruby file called potato.rb containing the following code:

class Potato
  def initialize
    @cooked = false
    puts "Cooked potato: #{@cooked}"

Running ruby potato.rb will open an IRB session where binding.irb is called, and you will see the following:

$ ruby potato.rb

From: potato.rb @ line 4 :

    1: class Potato
    2:   def initialize
    3:     @cooked = false
 => 4:     binding.irb
    5:     puts "Cooked potato: #{@cooked}"
    6:   end
    7: end


You can type any valid Ruby code and it will be evaluated in the current context. This allows you to debug without having to run your code repeatedly:

irb(#<Potato:0x00007feea1916670>):001:0> @cooked
=> false
irb(#<Potato:0x00007feea1916670>):002:0> self.class
=> Potato
irb(#<Potato:0x00007feea1916670>):003:0> caller.first
=> ".../2.5.1/lib/ruby/2.5.0/irb/workspace.rb:85:in `eval'"
irb(#<Potato:0x00007feea1916670>):004:0> @cooked = true
=> true

You can exit the IRB session with the exit command. Note that exiting will resume execution where binding.irb had paused it, as you can see from the output printed to standard output in this example:

irb(#<Potato:0x00007feea1916670>):005:0> exit
Cooked potato: true

See IRB for more information.

# File irb.rb, line 970
def irb
  IRB.setup(source_location[0], argv: [])
  workspace =
  binding_irb =
  binding_irb.context.irb_path = File.expand_path(source_location[0])