struct::tree v1(n)            Tcl Data Structures           struct::tree v1(n)



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NAME
       struct::tree v1 - Create and manipulate tree objects

SYNOPSIS
       package require Tcl  8.2

       package require struct::tree  ?1.2.2?

       treeName option ?arg arg ...?

       treeName append node ?-key key? value

       treeName children node

       treeName cut node

       treeName delete node ?node ...?

       treeName depth node

       treeName destroy

       treeName exists node

       treeName get node ?-key key?

       treeName getall node

       treeName keys node

       treeName keyexists node ?-key key?

       treeName index node

       treeName insert parent index ?child ?child ...??

       treeName isleaf node

       treeName lappend node ?-key key? value

       treeName move parent index node ?node ...?

       treeName next node

       treeName numchildren node

       treeName parent node

       treeName previous node

       treeName set node ?-key key? ?value?

       treeName size ?node?

       treeName splice parent from ?to? ?child?

       treeName swap node1 node2

       treeName unset node ?-key key?

       treeName walk node ?-order order? ?-type type? -command cmd

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DESCRIPTION
       The ::struct::tree command creates a new tree object with an associated
       global Tcl command whose name is treeName. This command may be used to
       invoke various operations on the tree. It has the following general
       form:

       treeName option ?arg arg ...?
              Option and the args determine the exact behavior of the command.

       A tree is a collection of named elements, called nodes, one of which is
       distinguished as a root, along with a relation ("parenthood") that
       places a hierarchical structure on the nodes. (Data Structures and
       Algorithms; Aho, Hopcroft and Ullman; Addison-Wesley, 1987).  In
       addition to maintaining the node relationships, this tree
       implementation allows any number of keyed values to be associated with
       each node.

       The element names can be arbitrary strings.

       A tree is thus similar to an array, but with three important
       differences:

       [1]    Trees are accessed through an object command, whereas arrays are
              accessed as variables. (This means trees cannot be local to a
              procedure.)

       [2]    Trees have a hierarchical structure, whereas an array is just an
              unordered collection.

       [3]    Each node of a tree has a separate collection of attributes and
              values. This is like an array where every value is a dictionary.

       The following commands are possible for tree objects:

       treeName append node ?-key key? value
              Appends a value to one of the keyed values associated with an
              node. If no key is specified, the key data is assumed.

       treeName children node
              Return a list of the children of node.

       treeName cut node
              Removes the node specified by node from the tree, but not its
              children.  The children of node are made children of the parent
              of the node, at the index at which node was located.

       treeName delete node ?node ...?
              Remove the specified nodes from the tree.  All of the nodes'
              children will be removed as well to prevent orphaned nodes.

       treeName depth node
              Return the number of steps from node node to the root node.

       treeName destroy
              Destroy the tree, including its storage space and associated
              command.

       treeName exists node
              Remove true if the specified node exists in the tree.

       treeName get node ?-key key?
              Return the value associated with the key key for the node node.
              If no key is specified, the key data is assumed.

       treeName getall node
              Returns a serialized list of key/value pairs (suitable for use
              with [array set]) for the node.

       treeName keys node
              Returns a list of keys for the node.

       treeName keyexists node ?-key key?
              Return true if the specified key exists for the node. If no key
              is specified, the key data is assumed.

       treeName index node
              Returns the index of node in its parent's list of children.  For
              example, if a node has nodeFoo, nodeBar, and nodeBaz as
              children, in that order, the index of nodeBar is 1.

       treeName insert parent index ?child ?child ...??
              Insert one or more nodes into the tree as children of the node
              parent. The nodes will be added in the order they are given. If
              parent is root, it refers to the root of the tree. The new nodes
              will be added to the parent node's child list at the index given
              by index. The index can be end in which case the new nodes will
              be added after the current last child.

              If any of the specified children already exist in treeName,
              those nodes will be moved from their original location to the
              new location indicated by this command.

              If no child is specified, a single node will be added, and a
              name will be generated for the new node. The generated name is
              of the form nodex, where x is a number. If names are specified
              they must neither contain whitespace nor colons (":").

              The return result from this command is a list of nodes added.

       treeName isleaf node
              Returns true if node is a leaf of the tree (if node has no
              children), false otherwise.

       treeName lappend node ?-key key? value
              Appends a value (as a list) to one of the keyed values
              associated with an node. If no key is specified, the key data is
              assumed.

       treeName move parent index node ?node ...?
              Make the specified nodes children of parent, inserting them into
              the parent's child list at the index given by index. Note that
              the command will take all nodes out of the tree before inserting
              them under the new parent, and that it determines the position
              to place them into after the removal, before the re-insertion.
              This behaviour is important when it comes to moving one or more
              nodes to a different index without changing their parent node.

       treeName next node
              Return the right sibling of node, or the empty string if node
              was the last child of its parent.

       treeName numchildren node
              Return the number of immediate children of node.

       treeName parent node
              Return the parent of node.

       treeName previous node
              Return the left sibling of node, or the empty string if node was
              the first child of its parent.

       treeName set node ?-key key? ?value?
              Set or get one of the keyed values associated with a node. If no
              key is specified, the key data is assumed.  Each node that is
              added to a tree has the value "" assigned to the key data
              automatically.  A node may have any number of keyed values
              associated with it.  If value is not specified, this command
              returns the current value assigned to the key; if value is
              specified, this command assigns that value to the key.

       treeName size ?node?
              Return a count of the number of descendants of the node node; if
              no node is specified, root is assumed.

       treeName splice parent from ?to? ?child?
              Insert a node named child into the tree as a child of the node
              parent. If parent is root, it refers to the root of the tree.
              The new node will be added to the parent node's child list at
              the index given by from.  The children of parent which are in
              the range of the indices from and to are made children of child.
              If the value of to is not specified it defaults to end.  If no
              name is given for child, a name will be generated for the new
              node.  The generated name is of the form nodex, where x is a
              number.  The return result from this command is the name of the
              new node.

       treeName swap node1 node2
              Swap the position of node1 and node2 in the tree.

       treeName unset node ?-key key?
              Remove a keyed value from the node node.  If no key is
              specified, the key data is assumed.

       treeName walk node ?-order order? ?-type type? -command cmd
              Perform a breadth-first or depth-first walk of the tree starting
              at the node node.  The type of walk, breadth-first or depth-
              first, is determined by the value of type; bfs indicates
              breadth-first, dfs indicates depth-first.  Depth-first is the
              default. The order of the walk, pre-, post-, both- or in-order
              is determined by the value of order; pre indicates pre-order,
              post indicates post-order, both indicates both-order and in
              indicates in-order. Pre-order is the default.

              Pre-order walking means that a parent node is visited before any
              of its children.  For example, a breadth-first search starting
              from the root will visit the root, followed by all of the root's
              children, followed by all of the root's grandchildren. Post-
              order walking means that a parent node is visited after any of
              its children. Both-order walking means that a parent node is
              visited before and after any of its children. In-order walking
              means that a parent node is visited after its first child and
              before the second. This is a generalization of in-order walking
              for binary trees and will do the right thing if a binary is
              walked. The combination of a breadth-first walk with in-order is
              illegal.

              As the walk progresses, the command cmd will be evaluated at
              each node.  Percent substitution will be performed on cmd before
              evaluation, just as in a bind script.  The following
              substitutions are recognized:

              %%     Insert the literal % character.

              %t     Name of the tree object.

              %n     Name of the current node.

              %a     Name of the action occurring; one of enter, leave, or
                     visit.  enter actions occur during pre-order walks; leave
                     actions occur during post-order walks; visit actions
                     occur during in-order walks.  In a both-order walk, the
                     command will be evaluated twice for each node; the action
                     is enter for the first evaluation, and leave for the
                     second.

BUGS, IDEAS, FEEDBACK
       This document, and the package it describes, will undoubtedly contain
       bugs and other problems.  Please report such in the category struct ::
       tree of the Tcllib SF Trackers
       [http://sourceforge.net/tracker/?group_id=12883].  Please also report
       any ideas for enhancements you may have for either package and/or
       documentation.

KEYWORDS
       tree

CATEGORY
       Data structures

COPYRIGHT
       Copyright (c) 2002 Andreas Kupries <andreas_kupries@users.sourceforge.net>




struct                               1.2.2                  struct::tree v1(n)
