Class: Stupidedi::Zipper::DanglingCursor

Inherits:

AbstractCursor

• Object
• AbstractCursor
• Stupidedi::Zipper::DanglingCursor

show all

Defined in:

lib/stupidedi/zipper/dangling_cursor.rb

Instance Attribute Summary (collapse)

• - (AbstractCursor) parent readonly

Querying the Tree Location (collapse)

• - (Integer) depth

  Distance from the root node.

• - (Boolean) first?
• - (Boolean) last?
• - (Boolean) leaf?
• - (Boolean) root?

Traversing the Tree (collapse)

• - (AbstractCursor) first

  Navigate to the first (leftmost) sibling node.

• - (AbstractCursor) last

  Navigate to the last (rightmost) sibling node.

• - (AbstractCursor) next

  Navigate to the next (rightward) sibling node.

• - (AbstractCursor) prev

  Navigate to the previous (leftward) sibling node.

• - (AbstractCursor) up

Editing the Tree (collapse)

• - (EditedCursor) delete

  Remove the current node, and navigate to the next (rightward) node if one exists.

• - (AbstractCursor) replace(node) (also: #prepend, #append)

  Replace the current node with the given node.

Instance Method Summary (collapse)

• - (DanglingCursor) initialize(parent) constructor

  A new instance of DanglingCursor.

• - (#leaf?, ...) node
• - (AbstractPath) path

Methods inherited from AbstractCursor

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

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# File 'lib/stupidedi/zipper/dangling_cursor.rb', line 9

def initialize(parent)
  @parent = parent
end

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# File 'lib/stupidedi/zipper/dangling_cursor.rb', line 7

def parent
  @parent
end

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# File 'lib/stupidedi/zipper/dangling_cursor.rb', line 94

def delete
  self
end

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# File 'lib/stupidedi/zipper/dangling_cursor.rb', line 38

def depth
  @parent.depth + 1
end

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# File 'lib/stupidedi/zipper/dangling_cursor.rb', line 73

def first
  self
end

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# File 'lib/stupidedi/zipper/dangling_cursor.rb', line 43

def first?
  true
end

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# File 'lib/stupidedi/zipper/dangling_cursor.rb', line 78

def last
  self
end

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# File 'lib/stupidedi/zipper/dangling_cursor.rb', line 48

def last?
  true
end

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# File 'lib/stupidedi/zipper/dangling_cursor.rb', line 28

def leaf?
  true
end

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

def next
  raise Exceptions::ZipperError,
    "cannot move to next after last node"
end

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# File 'lib/stupidedi/zipper/dangling_cursor.rb', line 14

def node
  raise Exceptions::ZipperError,
    "DanglingCursor#node should not be called"
end

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# File 'lib/stupidedi/zipper/dangling_cursor.rb', line 20

def path
  Hole.new([], @parent.path.parent, [])
end

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# File 'lib/stupidedi/zipper/dangling_cursor.rb', line 67

def prev
  raise Exceptions::ZipperError,
    "cannot move to prev before first node"
end

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# File 'lib/stupidedi/zipper/dangling_cursor.rb', line 86

def replace(node)
  @parent.append_child(node)
end

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# File 'lib/stupidedi/zipper/dangling_cursor.rb', line 33

def root?
  false
end

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# File 'lib/stupidedi/zipper/dangling_cursor.rb', line 56

def up
  @parent
end