Class: Stupidedi::Zipper::RootCursor

Inherits:
AbstractCursor show all
Defined in:
lib/stupidedi/zipper/root_cursor.rb

Instance Attribute Summary collapse

Querying the Tree Location collapse

Traversing the Tree collapse

Editing the Tree collapse

Instance Method Summary collapse

Methods inherited from AbstractCursor

#append_child, #between, #child, #children, #dangle, #descendant, #down, #flatten, #insert_left, #insert_right, #prepend_child

Constructor Details

#initialize(node) ⇒ RootCursor

Returns a new instance of RootCursor.



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# File 'lib/stupidedi/zipper/root_cursor.rb', line 13

def initialize(node)
  @node, @path =
    node, Root
end

Instance Attribute Details

#node ⇒ AbstractNode (readonly)

Returns:

  • (AbstractNode) 


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# File 'lib/stupidedi/zipper/root_cursor.rb', line 8

def node
  @node
end

#path ⇒ AbstractPath (readonly)

Returns:



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# File 'lib/stupidedi/zipper/root_cursor.rb', line 11

def path
  @path
end

Instance Method Details

#append(node) ⇒ EditedCursor, void

Insert a new sibling node after (to the right of) the current node, and navigate to the new sibling node

Returns:



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# File 'lib/stupidedi/zipper/root_cursor.rb', line 91

def append(node)
  raise Exceptions::ZipperError,
    "root node has no siblings"
end

#delete ⇒ EditedCursor, void

Remove the current node, and navigate to the next (rightward) node if one exists. Otherwise, navigate to the previous (leftward) node if one exists. Otherwise, create a placeholder where the next sibling node will be created.

Returns:



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# File 'lib/stupidedi/zipper/root_cursor.rb', line 111

def delete
  raise Exceptions::ZipperError,
    "cannot delete root node"
end

#depth ⇒ Integer

Distance from the root node

Returns:

  • (Integer) 


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# File 'lib/stupidedi/zipper/root_cursor.rb', line 22

def depth
  0
end

#first ⇒ AbstractCursor

Navigate to the first (leftmost) sibling node

Returns:



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# File 'lib/stupidedi/zipper/root_cursor.rb', line 50

def first
  self
end

#first?

True when the node has no leftward siblings



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# File 'lib/stupidedi/zipper/root_cursor.rb', line 27

def first?
  true
end

#last ⇒ AbstractCursor

Navigate to the last (rightmost) sibling node

Returns:



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# File 'lib/stupidedi/zipper/root_cursor.rb', line 55

def last
  self
end

#last?

True when the node has no rightward siblings



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# File 'lib/stupidedi/zipper/root_cursor.rb', line 32

def last?
  true
end

#leaf?

True if the node has no children



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# File 'lib/stupidedi/zipper/root_cursor.rb', line 37

def leaf?
  @node.leaf? or @node.children.empty?
end

#next ⇒ AbstractCursor, void

Navigate to the next (rightward) sibling node

Returns:



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# File 'lib/stupidedi/zipper/root_cursor.rb', line 61

def next
  raise Exceptions::ZipperError,
    "root node has no siblings"
end

#prepend(node) ⇒ EditedCursor, void

Insert a new sibling node before (to the left of) the current node, and navigate to the new sibling node

Returns:



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# File 'lib/stupidedi/zipper/root_cursor.rb', line 98

def prepend(node)
  raise Exceptions::ZipperError,
    "root node has no siblings"
end

#prev ⇒ AbstractCursor, void

Navigate to the previous (leftward) sibling node

Returns:



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# File 'lib/stupidedi/zipper/root_cursor.rb', line 68

def prev
  raise Exceptions::ZipperError,
    "root node has no siblings"
end

#replace(node) ⇒ AbstractCursor, RootCursor

Replace the current node with the given node

Returns:



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# File 'lib/stupidedi/zipper/root_cursor.rb', line 105

def replace(node)
  RootCursor.new(node)
end

#root ⇒ RootCursor

Navigate to the root node

Returns:



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# File 'lib/stupidedi/zipper/root_cursor.rb', line 75

def root
  self
end

#root?

True if the node has no parent



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# File 'lib/stupidedi/zipper/root_cursor.rb', line 42

def root?
  true
end

#up ⇒ AbstractCursor, void

Navigate to the parent node

Returns:



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# File 'lib/stupidedi/zipper/root_cursor.rb', line 81

def up
  raise Exceptions::ZipperError,
    "root node has no parent"
end