Simple inline debugger

debugger.rb

require 'pathname'
require 'pry'

# Usage:
#
# class YourClass
#   include Debugger
#   debugger_namespace "TheNamespace" # optional, defaults to file basename
#   debugger_show_line_numbers # optional
# 
#   def basic_printing_example
#     debug 'message'
#     # > TheNamespace:18 message
# 
#     debug [1,2,3,4]
#     # > TheNamespace:20 [1, 2, 3, 4]
#   end
# 
#   def open_pry_if_block_is_falsy
#     debug("debug message") { falsy_block }
#     # > TheNamespace:25 debug message
#     # pry(main)> (opens at debug call site)
#   end
# end

module Debugger
  def self.included(base)
    base.extend(ClassMethods)
  end

  module ClassMethods
    def debugger_namespace(namespace)
      @@debugger_namespace = namespace.to_s
    end

    def debugger_show_line_numbers(show = true)
      @@debugger_show_line_numbers = show
    end

    def debug(msg = :no_msg, &blk)
      loc = caller_locations(1, 1).first
      debugger_process_debug(loc, msg, &blk)
    end

    def debugger_process_debug(loc, msg, &blk)
      puts debug_message(loc, msg)
      return unless block_given?
      our_binding = blk.binding
      res = blk.call
      return our_binding.pry unless res
    end

    private

    def cyan(str)
      "\e[0;36m" +
        str +
        "\e[0;0m"
    end

    def debugger_namespace_name(loc)
      unless defined? @@debugger_namespace
        return Pathname.new(loc.path).basename.to_s
      end
      @@debugger_namespace
    end

    def debugger_line_numbers(loc)
      return '' unless defined? @@debugger_show_line_numbers
      ":#{loc.lineno}"
    end

    def debugger_user_message(msg)
      return '' if msg == :no_msg
      ' ' + msg.to_s
    end

    def debug_message(loc, msg)
      cyan(debugger_namespace_name(loc)) +
        debugger_line_numbers(loc) +
        debugger_user_message(msg)
    end
  end

  def debug(msg = :no_msg, &blk)
    loc = caller_locations(1, 1).first
    self.class.debugger_process_debug(loc, msg, &blk)
  end
end