Ubuntu Manpage: struct::tree_v1 - Create and manipulate tree objects

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

_________________________________________________________________________________________________

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 ...?
Removes 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
Returns 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?
Removes 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  Trackers
       [http://core.tcl.tk/tcllib/reportlist].  Please also report any ideas for enhancements you
       may have for either package and/or documentation.

KEYWORDS

       tree

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