clojure.zip

Functional hierarchical zipper, with navigation, editing,
and enumeration.  See Huet

Usage: (append-child loc item)

Inserts the item as the rightmost child of the node at this loc,
without moving

Usage: (branch? loc)

Returns true if the node at loc is a branch

Usage: (children loc)

Returns a seq of the children of node at loc, which must be a branch

Usage: (down loc)

Returns the loc of the leftmost child of the node at this loc, or
nil if no children

Usage: (edit loc f & args)

Replaces the node at this loc with the value of (f node args)

Usage: (end? loc)

Returns true if loc represents the end of a depth-first walk

Usage: (insert-child loc item)

Inserts the item as the leftmost child of the node at this loc,
without moving

Usage: (insert-left loc item)

Inserts the item as the left sibling of the node at this loc,
without moving

Usage: (insert-right loc item)

Inserts the item as the right sibling of the node at this loc,
without moving

Usage: (left loc)

Returns the loc of the left sibling of the node at this loc, or nil

Usage: (leftmost loc)

Returns the loc of the leftmost sibling of the node at this loc, or self

Usage: (lefts loc)

Returns a seq of the left siblings of this loc

Usage: (make-node loc node children)

Returns a new branch node, given an existing node and new
children. The loc is only used to supply the constructor.

Usage: (next loc)

Moves to the next loc in the hierarchy, depth-first. When reaching
the end, returns a distinguished loc detectable via end?. If already
at the end, stays there.

Usage: (node loc)

Returns the node at loc

Usage: (path loc)

Returns a seq of nodes leading to this loc

Usage: (prev loc)

Moves to the previous loc in the hierarchy, depth-first. If already
at the root, returns nil.

Usage: (remove loc)

Removes the node at loc, returning the loc that would have preceded
it in a depth-first walk.

Usage: (replace loc node)

Replaces the node at this loc, without moving

Usage: (right loc)

Returns the loc of the right sibling of the node at this loc, or nil

Usage: (rightmost loc)

Returns the loc of the rightmost sibling of the node at this loc, or self

Usage: (rights loc)

Returns a seq of the right siblings of this loc

Usage: (root loc)

zips all the way up and returns the root node, reflecting any
changes.

Usage: (seq-zip root)

Returns a zipper for nested sequences, given a root sequence

Usage: (up loc)

Returns the loc of the parent of the node at this loc, or nil if at
the top

Usage: (vector-zip root)

Returns a zipper for nested vectors, given a root vector

Usage: (xml-zip root)

Returns a zipper for xml elements (as from xml/parse),
given a root element

Usage: (zipper branch? children make-node root)

Creates a new zipper structure. 

branch? is a fn that, given a node, returns true if can have
children, even if it currently doesn't.

children is a fn that, given a branch node, returns a seq of its
children.

make-node is a fn that, given an existing node and a seq of
children, returns a new branch node with the supplied children.
root is the root node.