Class: DoubleLinkedList::Element

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/double_linked_list/element.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(datum, previous = nil, _next = nil) ⇒ Element

Returns a new instance of Element.



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# File 'lib/double_linked_list/element.rb', line 8

def initialize(datum, previous = nil, _next = nil)
  @datum = datum
  @previous = previous
  @_next = _next
end

Instance Attribute Details

#_next ⇒ Object Also known as: next

Returns the value of attribute _next.



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# File 'lib/double_linked_list/element.rb', line 6

def _next
  @_next
end

#datum ⇒ Object (readonly)

Returns the value of attribute datum.



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# File 'lib/double_linked_list/element.rb', line 5

def datum
  @datum
end

#previous ⇒ Object Also known as: prev

Returns the value of attribute previous.



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# File 'lib/double_linked_list/element.rb', line 6

def previous
  @previous
end

Instance Method Details

#_each(&block) ⇒ Object

Avoid calling myself on finds



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# File 'lib/double_linked_list/element.rb', line 23

def _each(&block)
  _next.each(&block) if _next
end

#_reverse_each(&block) ⇒ Object

This is done to avoid calling self in the block For not finding myself as the first element in the list



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# File 'lib/double_linked_list/element.rb', line 66

def _reverse_each(&block)
  previous.reverse_each(&block) if previous
end

#append(datum) ⇒ Object 



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# File 'lib/double_linked_list/element.rb', line 75

def append(datum)
  new_last = Element.new(datum, self, nil)
  self._next = new_last
  new_last
end

#chunk_by(acc, custom_dll = DoubleLinkedList, &block) ⇒ Object 



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# File 'lib/double_linked_list/element.rb', line 81

def chunk_by(acc, custom_dll = DoubleLinkedList, &block)
  if acc.empty?
    acc << custom_dll.from_a(self.datum)
  else
    if block.call(self, acc.last, acc)
      acc << custom_dll.from_a(self.datum)
    else
      acc.last << self.datum
    end
  end
  _next ? _next.chunk_by(acc, custom_dll, &block) : acc
end

#count ⇒ Object Also known as: included_next_count 



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# File 'lib/double_linked_list/element.rb', line 27

def count
  reduce(0) { |p| p + 1 }
end

#each(&block) ⇒ Object 



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# File 'lib/double_linked_list/element.rb', line 17

def each(&block)
  block.call self
  _next.each(&block) if _next
end

#find(datum) ⇒ Object 



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# File 'lib/double_linked_list/element.rb', line 48

def find(datum)
  find_next_by do |elem|
    elem.datum == datum
  end
end

#find_next_by(exclude_self = true, &block) ⇒ Object 



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# File 'lib/double_linked_list/element.rb', line 59

def find_next_by(exclude_self = true, &block)
  method = exclude_self ? :_each : :each
  _finder(method, &block)
end

#find_previous_by(exclude_self = true, &block) ⇒ Object 



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# File 'lib/double_linked_list/element.rb', line 54

def find_previous_by(exclude_self = true, &block)
  method = exclude_self ? :_reverse_each : :reverse_each
  _finder(method, &block)
end

#included_prev_count ⇒ Object 



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# File 'lib/double_linked_list/element.rb', line 44

def included_prev_count
  prev_count + 1
end

#next_count ⇒ Object 



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# File 'lib/double_linked_list/element.rb', line 32

def next_count
  c = 0
  _each { c += 1 }
  c
end

#prev_count ⇒ Object 



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# File 'lib/double_linked_list/element.rb', line 38

def prev_count
  c = 0
  _reverse_each { c += 1 }
  c
end

#reverse_each(&block) ⇒ Object 



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# File 'lib/double_linked_list/element.rb', line 70

def reverse_each(&block)
  block.call self
  previous.reverse_each(&block) if previous
end

#select_by(&block) ⇒ Object 



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# File 'lib/double_linked_list/element.rb', line 94

def select_by(&block)
  sequences = []
  find_multiple do |e|
    head_tail = block.call(e)
    if head_tail
      sequences << head_tail
    end
    head_tail
  end
  extract_sequences(sequences)
end