renato-zannon

import Control.Monad

data Tree a = EmptyTree | Node a (Tree a) (Tree a)

(<<) EmptyTree value = Node value EmptyTree EmptyTree
(<<) (Node value left right) newValue = if newValue < value
    then Node value (left << newValue) right
    else Node value left (right << newValue)

toArray EmptyTree = []

renato-zannon

module Inject
  class Injector
    def self.inject(*args, &block)
      options = args.last.kind_of?(Hash) ? args.pop : {}
      target  = options[:receiver] || block.binding.eval("self")

      modules = args

      modules.each { |mod| mod.before_inject(target) if mod.respond_to?(:before_inject)}
      return_value = new(modules).inject_into(target, &block)

renato-zannon

# It's common, while creating a bunch of very similar methods, to create
# a loop to define them all at once. (Very simple) example follows:

week_days = %w[sunday monday tuesday wednesday thursday friday saturday]

week_days.each do |day|
  define_method("events_on_#{day}") do
    events.select { |event| event.day == day }
  end
end