Module: Sanction::Tree

Included in:
Node
Defined in:
lib/sanction/tree.rb

Instance Method Summary collapse

Instance Method Details

#ancestors ⇒ Object

Get all of the ancestors for this node.



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# File 'lib/sanction/tree.rb', line 53

def ancestors
  ancestors = []
  if parent
    ancestors << parent
    parent.ancestors.each {|ancestor| ancestors << ancestor }
  end
  ancestors
end

#children ⇒ Object

Get the children of this node.



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# File 'lib/sanction/tree.rb', line 29

def children
  @children ||= []
end

#depth ⇒ Object

An integer representation of how deep in the tree this node is. The root node has a depth of 1, its children have a depth of 2, etc.



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# File 'lib/sanction/tree.rb', line 76

def depth
  ancestors.size + 1
end

#descendants ⇒ Object

Get all of the descendants of this node. All of its children, and its childrens’ children, and its childrens’ childrens’ children…



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# File 'lib/sanction/tree.rb', line 64

def descendants
  descendants = []
  if !children.empty?
    (descendants << children).flatten!
    children.each {|descendant| descendants << descendant.descendants }
    descendants.flatten!   
  end
  descendants
end

#graft(node) ⇒ Object

Append a node to this node’s children, and return the node.



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# File 'lib/sanction/tree.rb', line 108

def graft(node)
  node.instance_variable_set(:@parent, self)
  children << node
  node
end

#has_children? ⇒ Boolean

Does this node have children? Is it not a leaf node?

Returns:

  • (Boolean) 


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# File 'lib/sanction/tree.rb', line 48

def has_children?
  !leaf?
end

#height ⇒ Object

From Wikipedia: The height of a node is the length of the longest downward path to a leaf from that node. In other words, the length of this node to its furthest descendant.



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# File 'lib/sanction/tree.rb', line 83

def height
  if !leaf?
    descendants.collect {|child| child.depth }.uniq.size + 1
  else
    1
  end
end

#leaf? ⇒ Boolean

Is this node a leaf node? Is this node childless?

Returns:

  • (Boolean) 


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# File 'lib/sanction/tree.rb', line 15

def leaf?
  children.nil? || children.empty?
end

#only_child? ⇒ Boolean

Is this node the only child of its parent. Does it have any siblings?

Returns:

  • (Boolean) 


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# File 'lib/sanction/tree.rb', line 41

def only_child?
  if parent
    siblings.empty?
  end
end

#parent ⇒ Object

This node’s parent.



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# File 'lib/sanction/tree.rb', line 5

def parent
  @parent
end

#prune ⇒ Object

Abandon all of this node’s children.



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# File 'lib/sanction/tree.rb', line 101

def prune
  if children
    children.each {|child| child.unlink }
  end
end

#root ⇒ Object

Get the root node in this tree.



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# File 'lib/sanction/tree.rb', line 20

def root
  if root?
    self
  else
    parent.root
  end
end

#root? ⇒ Boolean

Is this node the root of the tree?

Returns:

  • (Boolean) 


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# File 'lib/sanction/tree.rb', line 10

def root?
  parent.nil?
end

#siblings ⇒ Object

Get the siblings of this node. The other children belonging to this node’s parent.



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# File 'lib/sanction/tree.rb', line 34

def siblings
  if parent
    parent.children.reject {|child| child == self }
  end
end

#unlink ⇒ Object

Orphan this node. Remove it from its parent node.



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# File 'lib/sanction/tree.rb', line 92

def unlink
  if parent
    parent.children.delete(self)
    self.instance_variable_set(:@parent, nil)
    return self
  end
end

#walk(&block) ⇒ Object

Recursively yield every node in the tree.



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# File 'lib/sanction/tree.rb', line 115

def walk(&block)
  if block_given?
    yield self
    children.each {|child| child.walk(&block) }
  end
end