class IRB::Inspector


irb(main):001:0> “what?” #=> omg! what?
irb(main):001:0> IRB.CurrentContext.inspect_mode = ins # => omg! #<IRB::Inspector:0x007f46f7ba7d28>
irb(main):001:0> ins = IRB::Inspector.new(proc{ |v| “omg! #{v}” })
Knowing this, you can create a rudimentary inspector as follows:
when the inspector is activated.
This also allows for an optional #init+, or init_proc, which is called
Inspector uses #inspect_value, or inspect_proc, for output of return values.
should be aware of:
In order to create your own custom inspector there are two things you
An irb inspector

def self.def_inspector(key, arg=nil, &block)

Inspector.def_inspector([key1,...], inspector)
Inspector.def_inspector(key, inspector)
Inspector.def_inspector([key1,..], init_p=nil){|v| v.inspect}
Inspector.def_inspector(key, init_p=nil){|v| v.inspect}

Example 
def self.def_inspector(key, arg=nil, &block)
  if block_given?
    inspector = IRB::Inspector(block, arg)
  else
    inspector = arg
  end
  case key
  when Array
    for k in key
      def_inspector(k, inspector)
    end
  when Symbol
    INSPECTORS[key] = inspector
    INSPECTORS[key.to_s] = inspector
  when String
    INSPECTORS[key] = inspector
    INSPECTORS[key.intern] = inspector
  else
    INSPECTORS[key] = inspector
  end
end

def self.keys_with_inspector(inspector)

during inspector definition.
Determines the inspector to use where +inspector+ is one of the keys passed 
def self.keys_with_inspector(inspector)
  INSPECTORS.select{|k,v| v == inspector}.collect{|k, v| k}
end

def init

dependent libraries.
Proc to call when the inspector is activated, good for requiring 
def init
  @init.call if @init
end

def initialize(inspect_proc, init_proc = nil)

output return values in irb.
Creates a new inspector object, using the given +inspect_proc+ when 
def initialize(inspect_proc, init_proc = nil)
  @init = init_proc
  @inspect = inspect_proc
end

def inspect_value(v)

Proc to call when the input is evaluated and output in irb. 
def inspect_value(v)
  @inspect.call(v)
rescue => e
  puts "An error occurred when inspecting the object: #{e.inspect}"
  begin
    puts "Result of Kernel#inspect: #{KERNEL_INSPECT.bind_call(v)}"
    ''
  rescue => e
    puts "An error occurred when running Kernel#inspect: #{e.inspect}"
    puts e.backtrace.join("\n")
    ''
  end
end