Class: Stupidedi::Zipper::MemoizedCursor
Instance Attribute Summary collapse
Querying the Tree Location
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Traversing the Tree
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Editing the Tree
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Instance Method Summary
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#append_child, #between, #child, #children, #dangle, #depth, #descendant, #down, #first?, #flatten, #insert_left, #insert_right, #last?, #prepend_child, #root
Constructor Details
#initialize(node, path, parent) ⇒ MemoizedCursor
Returns a new instance of MemoizedCursor.
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# File 'lib/stupidedi/zipper/memoized_cursor.rb', line 18
def initialize(node, path, parent)
@node, @path, @parent =
node, path, parent
end
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Instance Attribute Details
#node ⇒ #leaf?, ...
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# File 'lib/stupidedi/zipper/memoized_cursor.rb', line 9
def node
@node
end
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# File 'lib/stupidedi/zipper/memoized_cursor.rb', line 16
def parent
@parent
end
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# File 'lib/stupidedi/zipper/memoized_cursor.rb', line 12
def path
@path
end
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Instance Method Details
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# File 'lib/stupidedi/zipper/memoized_cursor.rb', line 88
def append(node)
EditedCursor.new(node,
Hole.new(@node.cons(@path.left), @path.parent, @path.right), @parent)
end
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# File 'lib/stupidedi/zipper/memoized_cursor.rb', line 105
def delete
if not last?
head, *tail = @path.right
EditedCursor.new(head,
Hole.new(@path.left, @path.parent, tail), @parent)
elsif not first?
head, *tail = @path.left
EditedCursor.new(head,
Hole.new(tail, @path.parent, @path.right), @parent)
else
parent =
@parent.node.copy(:children =>
@path.left.reverse.concat(@path.right))
EditedCursor.new(parent, @path.parent, @parent.parent).dangle
end
end
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# File 'lib/stupidedi/zipper/memoized_cursor.rb', line 73
def first
@parent.down
end
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# File 'lib/stupidedi/zipper/memoized_cursor.rb', line 78
def last
current = self
current = current.next until current.last?
current
end
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#leaf? ⇒ Boolean
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# File 'lib/stupidedi/zipper/memoized_cursor.rb', line 26
def leaf?
@node.leaf? or @node.children.empty?
end
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# File 'lib/stupidedi/zipper/memoized_cursor.rb', line 43
def next
@__next ||= begin
if last?
raise Exceptions::ZipperError,
"cannot move to next after last node"
end
head, *tail = @path.right
MemoizedCursor.new(head,
Hole.new(@node.cons(@path.left), @path.parent, tail), @parent)
end
end
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# File 'lib/stupidedi/zipper/memoized_cursor.rb', line 94
def prepend
EditedCursor.new(node,
Hole.new(@path.left, @path.parent, @node.cons(@path.right)), @parent)
end
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# File 'lib/stupidedi/zipper/memoized_cursor.rb', line 58
def prev
@__prev ||= begin
if first?
raise Exceptions::ZipperError,
"cannot move to prev before first node"
end
head, *tail = @path.left
MemoizedCursor.new(head,
Hole.new(tail, @path.parent, @node.cons(@path.right)), @parent)
end
end
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# File 'lib/stupidedi/zipper/memoized_cursor.rb', line 100
def replace(node)
EditedCursor.new(node, @path, @parent)
end
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#root? ⇒ Boolean
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# File 'lib/stupidedi/zipper/memoized_cursor.rb', line 30
def root?
false
end
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# File 'lib/stupidedi/zipper/memoized_cursor.rb', line 38
def up
@parent
end
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