Class: Utopia::Controller::Variables

Inherits:
Object
  • Object
show all
Defined in:
lib/utopia/controller/variables.rb

Overview

Provides a stack-based instance variable lookup mechanism. It can flatten a stack of controllers into a single hash.

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Variables

Returns a new instance of Variables.



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# File 'lib/utopia/controller/variables.rb', line 25

def initialize
  @controllers = []
end

Instance Method Details

#<<(controller) ⇒ Object 



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# File 'lib/utopia/controller/variables.rb', line 33

def << controller
  if top = self.top
    # This ensures that most variables will be at the top and controllers can naturally interactive with instance variables:
    controller.copy_instance_variables(top)
  end
  
  @controllers << controller
  
  return self
end

#[](key) ⇒ Object 



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# File 'lib/utopia/controller/variables.rb', line 75

def [] key
  fetch("@#{key}".to_sym, nil)
end

#fetch(key, default = self) ⇒ Object

We use self as a seninel



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# File 'lib/utopia/controller/variables.rb', line 45

def fetch(key, default=self)
  if controller = self.top
    if controller.instance_variables.include?(key)
      return controller.instance_variable_get(key)
    end
  end
  
  if block_given?
    yield(key)
  elsif !default.equal?(self)
    return default
  else
    raise KeyError.new(key)
  end
end

#to_hash ⇒ Object 



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# File 'lib/utopia/controller/variables.rb', line 61

def to_hash
  attributes = {}
  
  if controller = self.top
    controller.instance_variables.each do |name|
      key = name[1..-1].to_sym
      
      attributes[key] = controller.instance_variable_get(name)
    end
  end
  
  return attributes
end

#top ⇒ Object 



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# File 'lib/utopia/controller/variables.rb', line 29

def top
  @controllers.last
end