Short

class Out
  attr_writer :frm, :meth
  def initialize(frm = '%s', meth = :puts) =
    ( @frm, @meth = frm, meth )
  def →(*ar) = ( send @meth, @frm % [*ar] )
end

class Array
  alias_method :đ, :first
  alias_method :ł, :last
  (0..9).each {|no| define_method(:"_#{no}") { self[no] } }
end

class String
  def ĸ(rx, &bl) = ( scan(rx).each &bl )
end

O = Out.new('%s: %s')
def →(*args) = ( O.→(*args) )

# ==========================================

str = %(one 1 two 2 three 3 four 4)

str.ĸ(/(\w+) (\d)/) { → _1.đ, _1.ł }
O.frm = '%s'; O.meth = :p


→ [1,2,3]._0 # => 1
→ %w(one two three)._2 # => three
→ %(hejsan hoppsan i lingonskogen).split(' ')._3 # => lingonskogen