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

Initialize an empty controller stack.



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# File 'lib/utopia/controller/variables.rb', line 11

def initialize
	@controllers = []
end

Instance Method Details

#<<(controller) ⇒ Object

Push a controller after copying variables from the previous controller.



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# File 'lib/utopia/controller/variables.rb', line 24

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

Fetch a variable from the innermost controller.



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# File 'lib/utopia/controller/variables.rb', line 71

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 36

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

Convert the current controller's instance variables to attributes.



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# File 'lib/utopia/controller/variables.rb', line 54

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

Return the innermost controller.



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# File 'lib/utopia/controller/variables.rb', line 17

def top
	@controllers.last
end