use pattern of alias, and advice

gistfile1.rb

# The pattern for using alias

  alias_method :__behavior__, :behavior
  remove_method :behavior
  define_method :behavior do
    # ...
    __behavior__
    # ...
  end

# Does that ring some bells?

class Module
   def advice_method methd, when_={}
     m = method methd
     remove_method methd
     define_method methd do | *args, &blk |
       largs = args
       lblk  = blk
       largs, lblk = when_.fetch( :input ){ lambda{ | *a, &b | [ a, b ] } }.call( *args, &blk )
       when_.fetch( :before, empty }.call( *largs, &lblk )
       result = m.bind( self ).call( *largs, &lblk )
       when_.fetch( :after, empty ).call( *largs, &lblk )
       when_.fetch( :output ){ return result }.call( *largs, &lblk )
     end
   end

   def around methd, before, after
     adv_method methd, before: before, after: after
   end

   def before methd, &blk
     advice_method methd, before: blk
   end
   # ...
end