`p` and `puts` Behind The Scene

display_complex_objects.rb

# `puts` method calls `to_s` method when a class is given as param
# `p` method calls `inspect` method when a class is given as param

class Factory
  def initialize
    @workers  = { workers: [] }   # A lot of workers
    @machines = { machines: [] }  # A lot of machines
  end

  def add_worker(name)
    @workers[:workers] << { :name => name }
  end

  def add_machines(id)
    @machines[:machines] << { :id => id }
  end

  def to_s
    w = @workers[:workers].map { |worker| worker[:name] }.join(', ')
    m = @machines[:machines].map { |machine| machine[:id] }.join(', ')
    "Worker List: #{w} -- Machine List: #{m}"
  end

  def inspect
    "You're trying to dig :)"
  end
end

factory = Factory.new

factory.add_worker('Jim')
factory.add_worker('Larry')
factory.add_worker('Doug')

factory.add_machines('12QC-2323')
factory.add_machines('12QC-2324')
factory.add_machines('12QC-2325')

puts factory
p factory

# Output:
#
# $> ruby display_complex_objects.rb
# Worker List: Jim, Larry, Doug -- Machine List: 12QC-2323, 12QC-2324, 12QC-2325
# You're trying to dig :)
# $>