Class: Hyperactive::List::Head

Inherits:
Record::Bass show all
Defined in:
lib/hyperactive/list.rb

Overview

A List head.

Constant Summary

Constants inherited from Record::Bass

Record::Bass::HOST

Instance Attribute Summary collapse

Attributes inherited from Record::Bass

#record_id

Instance Method Summary collapse

Methods inherited from Record::Bass

create_hooks, #destroy, destroy_hooks, find, get_instance, index_by, reject, #save_hook, save_hooks, select, setup, transaction

Constructor Details

#initialize ⇒ Head

Create a Head.

NB: As usual, dont call this. Use Head.get_instance instead.



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# File 'lib/hyperactive/list.rb', line 47

def initialize
  @size = 0
  @first_element = @last_element = nil
end

Instance Attribute Details

#first_element ⇒ Object (readonly)

Returns the value of attribute first_element.



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# File 'lib/hyperactive/list.rb', line 40

def first_element
  @first_element
end

#last_element ⇒ Object (readonly)

Returns the value of attribute last_element.



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# File 'lib/hyperactive/list.rb', line 40

def last_element
  @last_element
end

#size ⇒ Object (readonly)

Returns the value of attribute size.



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# File 'lib/hyperactive/list.rb', line 40

def size
  @size
end

Instance Method Details

#<<(v) ⇒ Object

Push v onto the end of this list.



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# File 'lib/hyperactive/list.rb', line 69

def <<(v)
  if @first_element
    new_element = Element.get_instance
    new_element.value = v
    new_element.previous = @last_element
    @last_element.next = new_element
    @last_element = new_element
  else
    start(v)
  end
  @size += 1
  return v
end

#first ⇒ Object

Return the first value of the list.



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# File 'lib/hyperactive/list.rb', line 55

def first
  @first_element.value
end

#last ⇒ Object

Return the last value of the list.



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# File 'lib/hyperactive/list.rb', line 62

def last
  @last_element.value
end

#pop ⇒ Object

Remove the last value from this list and return it.



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# File 'lib/hyperactive/list.rb', line 103

def pop
  v = nil
  if size > 1
    element = @last_element
    @last_element = element.previous
    @last_element.next = nil
    v = element.value
    element.destroy
  else
    v = @first_element.value
    @first_element.destroy
    @first_element = @last_element = nil
  end
  @size -= 1
  return v
end

#shift ⇒ Object

Remove the first value from this list and return it.



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# File 'lib/hyperactive/list.rb', line 123

def shift
  v = nil
  if size > 1
    element = @first_element
    @first_element = element.next
    @first_element.previous = nil
    v = element.value
    element.destroy
  else
    v = @first_element.value
    @first_element.destroy
    @first_element = @last_element = nil
  end
  @size -= 1
  return v
end

#unshift(v) ⇒ Object

Push v onto the beginning of this list.



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# File 'lib/hyperactive/list.rb', line 86

def unshift(v)
  if @first_element
    new_element = Element.get_instance
    new_element.value = v
    new_element.next = @first_element
    @first_element.previous = new_element
    @first_element = new_element
  else
    start(v)
  end 
  @size += 1
  return v
end