class Binding
Public Instance Methods
irb(show_code: true)
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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 binding.irb puts "Cooked potato: #{@cooked}" end end Potato.new
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 8: 9: Potato.new irb(#<Potato:0x00007feea1916670>):001:0>
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 1578 def irb(show_code: true) # Setup IRB with the current file's path and no command line arguments IRB.setup(source_location[0], argv: []) unless IRB.initialized? # Create a new workspace using the current binding workspace = IRB::WorkSpace.new(self) # Print the code around the binding if show_code is true STDOUT.print(workspace.code_around_binding) if show_code # Get the original IRB instance debugger_irb = IRB.instance_variable_get(:@debugger_irb) irb_path = File.expand_path(source_location[0]) if debugger_irb # If we're already in a debugger session, set the workspace and irb_path for the original IRB instance debugger_irb.context.replace_workspace(workspace) debugger_irb.context.irb_path = irb_path # If we've started a debugger session and hit another binding.irb, we don't want # to start an IRB session instead, we want to resume the irb:rdbg session. IRB::Debug.setup(debugger_irb) IRB::Debug.insert_debug_break debugger_irb.debug_break else # If we're not in a debugger session, create a new IRB instance with the current # workspace binding_irb = IRB::Irb.new(workspace, from_binding: true) binding_irb.context.irb_path = irb_path binding_irb.run(IRB.conf) binding_irb.debug_break end end