module IRB::MethodExtender

def def_post_proc(base_method, extend_method)

+extend_method+.
Extends the given +base_method+ with a postfix call to the given 
def def_post_proc(base_method, extend_method)
  base_method = base_method.to_s
  extend_method = extend_method.to_s
  alias_name = new_alias_name(base_method)
  module_eval %[
    alias_method alias_name, base_method
    def #{base_method}(*opts)
      __send__ :#{alias_name}, *opts
      __send__ :#{extend_method}, *opts
    end
  ]
end

def def_pre_proc(base_method, extend_method)

+extend_method+.
Extends the given +base_method+ with a prefix call to the given 
def def_pre_proc(base_method, extend_method)
  base_method = base_method.to_s
  extend_method = extend_method.to_s
  alias_name = new_alias_name(base_method)
  module_eval %[
    alias_method alias_name, base_method
    def #{base_method}(*opts)
      __send__ :#{extend_method}, *opts
      __send__ :#{alias_name}, *opts
    end
  ]
end

def new_alias_name(name, prefix = "__alias_of__", postfix = "__")

new_alias_name('bar') #=> __alias_of__bar__2
def bar; end
new_alias_name('foo') #=> __alias_of__foo__

Usually returns #{prefix}#{name}#{postfix}, example:

Returns a unique method name to use as an alias for the given +name+. 
def new_alias_name(name, prefix = "__alias_of__", postfix = "__")
  base_name = "#{prefix}#{name}#{postfix}"
  all_methods = instance_methods(true) + private_instance_methods(true)
  same_methods = all_methods.grep(/^#{Regexp.quote(base_name)}[0-9]*$/)
  return base_name if same_methods.empty?
  no = same_methods.size
  while !same_methods.include?(alias_name = base_name + no)
    no += 1
  end
  alias_name
end