zzak

# ====================
# Spell: Dynamic Proxy
# ====================

# Forward to another object any messages that don’t match a method.

class MyDynamicProxy
  def initialize(target)
    @target = target
  end

zzak

# =================
# Spell: Flat Scope
# =================

# Use a closure to share variables between two scopes.

class C
  def an_attribute
    @attr
  end

zzak

# ===================
# Spell: Ghost Method
# ===================

# Respond to a message that doesn’t have an associated method.

class C
  def method_missing(name, *args)
    name.to_s.reverse
  end

zzak

# ==================
# Spell: Hook Method
# ==================

# Override a method to intercept object model events.

$INHERITORS = []

class C
  def self.inherited(subclass)

zzak

# ====================
# Spell: Kernel Method
# ====================

# Define a method in module Kernel to make the method available to all objects.

module Kernel
  def a_method
    "a kernel method"
  end

zzak

# =============================
# Spell: Lazy Instance Variable
# =============================

# Wait until the first access to initialize an instance variable.

class C
  def attribute
    @attribute = @attribute || "some value"
  end

zzak

# ===================
# Spell: Mimic Method
# ===================

# Disguise a method as another language construct.

def BaseClass(name)
  name == "string" ? String : Object
end

zzak

# ==================
# Spell: Monkeypatch
# ==================

# Change the features of an existing class.

"abc".reverse # => "cba"

class String
  def reverse

zzak

# ======================
# Spell: Named Arguments
# ======================

# Collect method arguments into a hash to identify them by name.

def my_method(args)
  args[:arg2]
end

zzak

# ================
# Spell: Namespace
# ================

# Define constants within a module to avoid name clashes.

module MyNamespace
  class Array
    def to_s
      "my class"