Some common but neat ruby tricks

beautiful.rb

class Symbol
  def to_proc
    proc { |obj, *args| obj.send(self, *args) } 
  end
end

class Array
  def sum
    inject :+
  end
  
  def product
    inject :*
  end
end

class Fixnum
  def f!
    (1..self).to_a.product
  end
  
  terms = {:minute => 60, :hour => 3600, :day => 86400}
  
  terms.each do |term, length|
    define_method term do
      self*length
    end
    alias_method "#{term}s", term
  end
  
  def ago
    Time.now - self
  end
end



puts (2.days+25.minutes).ago

puts 5.f!

puts [1, 2, 3, 4].product