Provided by: blt-dev_2.4z-7ubuntu2_amd64 
NAME
tree - Create and manage tree data objects.
SYNOPSIS
blt::tree create ?treeName?
blt::tree destroy treeName...
blt::tree names ?pattern?
_________________________________________________________________
DESCRIPTION
The tree command creates tree data objects. A tree object is general ordered tree of nodes. Each node
has both a label and a key-value list of data. Data can be heterogeneous, since nodes do not have to
contain the same data keys. It is associated with a Tcl command that you can use to access and modify
the its structure and data. Tree objects can also be managed via a C API.
INTRODUCTION
EXAMPLE
SYNTAX
tree create ?treeName?
Creates a new tree object. The name of the new tree is returned. If no treeName argument is
present, then the name of the tree is automatically generated in the form "tree0", "tree1", etc.
If the substring "#auto" is found in treeName, it is automatically substituted by a generated
name. For example, the name .foo.#auto.bar will be translated to .foo.tree0.bar.
A new Tcl command (by the same name as the tree) is also created. Another Tcl command or tree
object can not already exist as treeName. If the Tcl command is deleted, the tree will also be
freed. The new tree will contain just the root node. Trees are by default, created in the
current namespace, not the global namespace, unless treeName contains a namespace qualifier, such
as "fred::myTree".
tree destroy treeName...
Releases one of more trees. The Tcl command associated with treeName is also removed. Trees are
reference counted. The internal tree data object isn't destroyed until no one else is using the
tree.
tree names ?pattern?
Returns the names of all tree objects. if a pattern argument is given, then the only those trees
whose name matches pattern will be listed.
NODE IDS AND TAGS
Nodes in a tree object may be referred in either of two ways: by id or by tag. Each node has a unique
serial number or id that is assigned to that node when it's created. The id of an node never changes and
id numbers are not re-used.
A node may also have any number of tags associated with it. A tag is just a string of characters, and it
may take any form except that of an integer. For example, "x123" is valid, but "123" isn't. The same
tag may be associated with many different nodes. This is commonly done to group nodes in various
interesting ways.
There are two built-in tags: The tag all is implicitly associated with every node in the tree. It may be
used to invoke operations on all the nodes in the tree. The tag root is managed automatically by the
tree object. It applies to the node currently set as root.
When specifying nodes in tree object commands, if the specifier is an integer then it is assumed to refer
to the single node with that id. If the specifier is not an integer, then it is assumed to refer to all
of the nodes in the tree that have a tag matching the specifier. The symbol node is used below to
indicate that an argument specifies either an id that selects a single node or a tag that selects zero or
more nodes. Many tree commands only operate on a single node at a time; if node is specified in a way
that names multiple items, then an error "refers to more than one node" is generated.
NODE MODIFIERS
You can also specify node in relation to another node by appending one or more modifiers to the node id
or tag. A modifier refers to a node in relation to the specified node. For example, "root->firstchild"
selects the first subtree of the root node.
The following modifiers are available:
firstchild
Selects the first child of the node.
lastchild Selects the last child of the node.
next Selects the next node in preorder to the node.
nextsibling
Selects the next sibling of the node.
parent Selects the parent of the node.
previous Selects the previous node in preorder to the node.
prevsibling
Selects the previous sibling of the node.
"label" Selects the node whose label is label. Enclosing label in quotes indicates to always
search for a node by its label (for example, even if the node is labeled "parent").
It's an error the node can't be found. For example, lastchild and firstchild will generate errors if the
node has no children. The exception to this is the index operation. You can use index to test if a
modifier is valid.
TREE OPERATIONS
Once you create a tree object, you can use its Tcl command to query or modify it. The general form is
treeName operation ?arg?... Both operation and its arguments determine the exact behavior of the
command. The operations available for trees are listed below.
treeName ancestor node1 node2
Returns the mutual ancestor of the two nodes node1 and node2. The ancestor can be one of the two
nodes. For example, if node1 and node2 are the same nodes, their ancestor is node1.
treeName apply node ?switches?
Runs commands for all nodes matching the criteria given by switches for the subtree designated by
node. By default all nodes match, but you can set switches to narrow the match. This operation
differs from find in two ways: 1) Tcl commands can be invoked both pre- and post-traversal of a
node and 2) the tree is always traversed in depth first order.
The -exact, -glob, and -regexp switches indicate both what kind of pattern matching to perform and
the pattern. By default each pattern will be compared with the node label. You can set more than
one of these switches. If any of the patterns match (logical or), the node matches. If the -key
switch is used, it designates the data field to be matched.
The valid switches are listed below:
-depth number
Descend at most number (a non-negative integer) levels If number is 1 this means only
apply the tests to the children of node.
-exact string
Matches each node using string. The node must match string exactly.
-glob string
Test each node to string using global pattern matching. Matching is done in a fashion
similar to that used by the C-shell.
-invert Select non-matching nodes. Any node that doesn't match the given criteria will be
selected.
-key key If pattern matching is selected (using the -exact, -glob, or -regexp switches), compare
the values of the data field keyed by key instead of the node's label. If no pattern
matching switches are set, then any node with this data key will match.
-leafonly Only test nodes with no children.
-nocase Ignore case when matching patterns.
-path Use the node's full path when comparing nodes. The node's full path is a list of
labels, starting from the root of each ancestor and the node itself.
-precommand command
Invoke command for each matching node. Before command is invoked, the id of the node is
appended. You can control processing by the return value of command. If command
generates an error, processing stops and the find operation returns an error. But if
command returns break, then processing stops, no error is generated. If command returns
continue, then processing stops on that subtree and continues on the next.
-postcommand command
Invoke command for each matching node. Before command is invoked, the id of the node is
appended. You can control processing by the return value of command. If command
generates an error, processing stops and the find operation returns an error. But if
command returns break, then processing stops, no error is generated. If command returns
continue, then processing stops on that subtree and continues on the next.
-regexp string
Test each node using string as a regular expression pattern.
-tag string
Only test nodes that have the tag string.
treeName attach treeObject
Attaches to an existing tree object treeObject. This is for cases where the tree object was
previously created via the C API. The current tree associated with treeName is discarded. In
addition, the current set of tags, notifier events, and traces are removed.
treeName children node
Returns a list of children for node. If node is a leaf, then an empty string is returned.
treeName copy srcNode ?destTree? parentNode ?switches?
Copies srcNode into parentNode. Both nodes srcNode and parentNode must already exist. The id of
the new node is returned. You can copy from one tree to another. If a destTree argument is
present, it indicates the name of the destination tree. By default both the source and
destination trees are the same. The valid switches are listed below:
-label string
Label destNode as string. By default, destNode has the same label as srcNode.
-overwrite
Overwrite nodes that already exist. Normally nodes are always created, even if there
already exists a node by the same name. This switch indicates to add or overwrite the
node's data fields.
-recurse
Recursively copy all the subtrees of srcNode as well. In this case, srcNode can't be an
ancestor of destNode as it would result in a cyclic copy.
-tags Copy tag inforation. Normally the following node is copied: its label and data fields.
This indicates to copy tags as well.
treeName degree node
Returns the number of children of node.
treeName delete node...
Recursively deletes one or more nodes from the tree. The node and all its descendants are
removed. The one exception is the root node. In this case, only its descendants are removed.
The root node will remain. Any tags or traces on the nodes are released.
treeName depth node
Returns the depth of the node. The depth is the number of steps from the node to the root of the
tree. The depth of the root node is 0.
treeName dump node
Returns a list of the paths and respective data for node and its descendants. The subtree
designated by node is traversed returning the following information for each node: 1) the node's
path relative to node, 2) a sublist key value pairs representing the node's data fields, and 3) a
sublist of tags. This list returned can be used later to copy or restore the tree with the
restore operation.
treeName dumpfile node fileName
Writes a list of the paths and respective data for node and its descendants to the given file
fileName. The subtree designated by node is traversed returning the following information for
each node: 1) the node's path relative to node, 2) a sublist key value pairs representing the
node's data fields, and 3) a sublist of tags. This list returned can be used later to copy or
restore the tree with the restore operation.
treeName exists node ?key?
Indicates if node exists in the tree. If a key argument is present then the command also
indicates if the named data field exists.
treeName find node ?switches?
Finds for all nodes matching the criteria given by switches for the subtree designated by node. A
list of the selected nodes is returned. By default all nodes match, but you can set switches to
narrow the match.
The -exact, -glob, and -regexp switches indicate both what kind of pattern matching to perform and
the pattern. By default each pattern will be compared with the node label. You can set more than
one of these switches. If any of the patterns match (logical or), the node matches. If the -key
switch is used, it designates the data field to be matched.
The order in which the nodes are traversed is controlled by the -order switch. The possible
orderings are preorder, postorder, inorder, and breadthfirst. The default is postorder.
The valid switches are listed below:
-addtag string
Add the tag string to each selected node.
-count number
Stop processing after number (a positive integer) matches.
-depth number
Descend at most number (a non-negative integer) levels If number is 1 this means only
apply the tests to the children of node.
-exact string
Matches each node using string. The node must match string exactly.
-exec command
Invoke command for each matching node. Before command is invoked, the id of the node is
appended. You can control processing by the return value of command. If command
generates an error, processing stops and the find operation returns an error. But if
command returns break, then processing stops, no error is generated. If command returns
continue, then processing stops on that subtree and continues on the next.
-glob string
Test each node to string using global pattern matching. Matching is done in a fashion
similar to that used by the C-shell.
-invert Select non-matching nodes. Any node that doesn't match the given criteria will be
selected.
-key key Compare the values of the data field keyed by key instead of the node's label. If no
pattern is given (-exact, -glob, or -regexp switches), then any node with this data key
will match.
-leafonly Only test nodes with no children.
-nocase Ignore case when matching patterns.
-order string
Traverse the tree and process nodes according to string. String can be one of the
following:
breadthfirst
Process the node and the subtrees at each sucessive level. Each node on a
level is processed before going to the next level.
inorder Recursively process the nodes of the first subtree, the node itself, and any
the remaining subtrees.
postorder Recursively process all subtrees before the node.
preorder Recursively process the node first, then any subtrees.
-path Use the node's full path when comparing nodes.
-regexp string
Test each node using string as a regular expression pattern.
-tag string
Only test nodes that have the tag string.
treeName findchild node label
Searches for a child node Ilabel in node. The id of the child node is returned if found.
Otherwise -1 is returned.
treeName firstchild node
Returns the id of the first child in the node's list of subtrees. If node is a leaf (has no
children), then -1 is returned.
treeName get node ?key? ?defaultValue?
Returns a list of key-value pairs of data for the node. If key is present, then onlyx the value
for that particular data field is returned. It's normally an error if node does not contain the
data field key. But if you provide a defaultValue argument, this value is returned instead (node
will still not contain key). This feature can be used to access a data field of node without
first testing if it exists. This operation may trigger read data traces.
treeName index node
Returns the id of node. If node is a tag, it can only specify one node. If node does not
represent a valid node id or tag, or has modifiers that are invalid, then -1 is returned.
treeName insert parent ?switches?
Inserts a new node into parent node parent. The id of the new node is returned. The following
switches are available:
-after child
Position node after child. The node child must be a child of parent.
-at number
Inserts the node into parent's list of children at position number. The default is to
append node.
-before child
Position node before child. The node child must be a child of parent.
-data dataList
Sets the value for each data field in dataList for the new node. DataList is a list of
key-value pairs.
-label string
Designates the labels of the node as string. By default, nodes are labeled as node0,
node1, etc.
-node id Designates the id for the node. Normally new ids are automatically generated. This
allows you to create a node with a specific id. It is an error if the id is already
used by another node in the tree.
-tags tagList
Adds each tag in tagList to the new node. TagList is a list of tags, so be careful if a
tag has embedded space.
treeName is property args
Indicates the property of a node. Both property and args determine the property being tested.
Returns 1 if true and 0 otherwise. The following property and args are valid:
ancestor node1 node2
Indicates if node1 is an ancestor of node2.
before node1 node2
Indicates if node1 is before node2 in depth first traversal.
leaf node Indicates if node is a leaf (it has no subtrees).
root node Indicates if node is the designated root. This can be changed by the root operation.
treeName label node ?newLabel?
Returns the label of the node designated by node. If newLabel is present, the node is relabeled
using it as the new label.
treeName lastchild node
Returns the id of the last child in the node's list of subtrees. If node is a leaf (has no
children), then -1 is returned.
treeName move node newParent ?switches?
Moves node into newParent. Node is appended to the list children of newParent. Node can not be an
ancestor of newParent. The valid flags for switches are described below.
-after child
Position node after child. The node child must be a child of newParent.
-at number
Inserts node into parent's list of children at position number. The default is to append
the node.
-before child
Position node before child. The node child must be a child of newParent.
treeName next node
Returns the next node from node in a preorder traversal. If node is the last node in the tree,
then -1 is returned.
treeName nextsibling node
Returns the node representing the next subtree from node in its parent's list of children. If
node is the last child, then -1 is returned.
treeName notify args
Manages notification events that indicate that the tree structure has been changed. See the
NOTIFY OPERATIONS section below.
treeName parent node
Returns the parent node of node. If node is the root of the tree, then -1 is returned.
treeName path node
Returns the full path (from root) of node.
treeName position node
Returns the position of the node in its parent's list of children. Positions are numbered from 0.
The position of the root node is always 0.
treeName previous node
Returns the previous node from node in a preorder traversal. If node is the root of the tree,
then -1 is returned.
treeName prevsibling node
Returns the node representing the previous subtree from node in its parent's list of children. If
node is the first child, then -1 is returned.
treeName restore node dataString switches
Performs the inverse function of the dump operation, restoring nodes to the tree. The format of
dataString is exactly what is returned by the dump operation. It's a list containing information
for each node to be restored. The information consists of 1) the relative path of the node, 2) a
sublist of key value pairs representing the node's data, and 3) a list of tags for the node.
Nodes are created starting from node. Nodes can be listed in any order. If a node's path
describes ancestor nodes that do not already exist, they are automatically created. The valid
switches are listed below:
-overwrite
Overwrite nodes that already exist. Normally nodes are always created, even if there
already exists a node by the same name. This switch indicates to add or overwrite the
node's data fields.
treeName restorefile node fileName switches
Performs the inverse function of the dumpfile operation, restoring nodes to the tree from the file
fileName. The format of fileName is exactly what is returned by the dumpfile operation. It's a
list containing information for each node to be restored. The information consists of 1) the
relative path of the node, 2) a sublist of key value pairs representing the node's data, and 3) a
list of tags for the node. Nodes are created starting from node. Nodes can be listed in any
order. If a node's path describes ancestor nodes that do not already exist, they are
automatically created. The valid switches are listed below:
-overwrite
Overwrite nodes that already exist. Normally nodes are always created, even if there
already exists a node by the same name. This switch indicates to add or overwrite the
node's data fields.
treeName root ?node?
Returns the id of the root node. Normally this is node 0. If a node argument is provided, it
will become the new root of the tree. This lets you temporarily work within a subset of the tree.
Changing root affects operations such as next, path, previous, etc.
treeName set node key value ?key value...?
Sets one or more data fields in node. Node may be a tag that represents several nodes. Key is the
name of the data field to be set and value is its respective value. This operation may trigger
write and create data traces.
treeName size node
Returns the number of nodes in the subtree. This includes the node and all its descendants. The
size of a leaf node is 1.
treeName sort node ?switches?
-ascii Compare strings using the ASCII collation order.
-command string
Use command string as a comparison command. To compare two elements, evaluate a Tcl
script consisting of command with the two elements appended as additional arguments.
The script should return an integer less than, equal to, or greater than zero if the
first element is to be considered less than, equal to, or greater than the second,
respectively.
-decreasing
Sort in decreasing order (largest items come first).
-dictionary
Compare strings using a dictionary-style comparison. This is the same as -ascii except
(a) case is ignored except as a tie-breaker and (b) if two strings contain embedded
numbers, the numbers compare as integers, not characters. For example, in -dictionary
mode, bigBoy sorts between bigbang and bigboy, and x10y sorts between x9y and x11y.
-integer Compare the nodes as integers.
-key string
Sort based upon the node's data field keyed by string. Normally nodes are sorted
according to their label.
-path Compare the full path of each node. The default is to compare only its label.
-real Compare the nodes as real numbers.
-recurse Recursively sort the entire subtree rooted at node.
-reorder Recursively sort subtrees for each node. Warning. Unlike the normal flat sort, where a
list of nodes is returned, this will reorder the tree.
treeName tag args
Manages tags for the tree object. See the TAG OPERATIONS section below.
treeName trace args
Manages traces for data fields in the tree object. Traces cause Tcl commands to be executed
whenever a data field of a node is created, read, written, or unset. Traces can be set for a
specific node or a tag, representing possibly many nodes. See the TRACE OPERATIONS section below.
treeName unset node key...
Removes one or more data fields from node. Node may be a tag that represents several nodes. Key
is the name of the data field to be removed. It's not an error is node does not contain key.
This operation may trigger unset data traces.
TAG OPERATIONS
Tags are a general means of selecting and marking nodes in the tree. A tag is just a string of
characters, and it may take any form except that of an integer. The same tag may be associated with many
different nodes.
There are two built-in tags: The tag all is implicitly associated with every node in the tree. It may be
used to invoke operations on all the nodes in the tree. The tag root is managed automatically by the
tree object. It specifies the node that is currently set as the root of the tree.
Most tree operations use tags. And several operations let you operate on multiple nodes at once. For
example, you can use the set operation with the tag all to set a data field in for all nodes in the tree.
Tags are invoked by the tag operation. The general form is treeName tag operation ?arg?... Both
operation and its arguments determine the exact behavior of the command. The operations available for
tags are listed below.
treeName tag add string node...
Adds the tag string to one of more nodes.
treeName tag delete string node...
Deletes the tag string from one or more nodes.
treeName tag forget string
Removes the tag string from all nodes. It's not an error if no nodes are tagged as string.
treeName tag names ?node?
Returns a list of tags used by the tree. If a node argument is present, only those tags used by
node are returned.
treeName tag nodes string
Returns a list of nodes that have the tag string. If no node is tagged as string, then an empty
string is returned.
TRACE OPERATIONS
Data fields can be traced much in the same way that you can trace Tcl variables. Data traces cause Tcl
commands to be executed whenever a particular data field of a node is created, read, written, or unset.
A trace can apply to one or more nodes. You can trace a specific node by using its id, or a group of
nodes by a their tag.
The tree's get, set, and unset operations can trigger various traces. The get operation can cause a read
trace to fire. The set operation causes a write trace to fire. And if the data field is written for the
first time, you will also get a create trace. The unset operation triggers unset traces.
Data traces are invoked by the trace operation. The general form is treeName trace operation ?arg?...
Both operation and its arguments determine the exact behavior of the command. The operations available
for traces are listed below.
treeName trace create node key ops command
Creates a trace for node on data field key. Node can refer to more than one node (for example,
the tag all). If node is a tag, any node with that tag can possibly trigger a trace, invoking
command. Command is command prefix, typically a procedure name. Whenever a trace is triggered,
four arguments are appended to command before it is invoked: treeName, id of the node, key and,
ops. Note that no nodes need have the field key. A trace identifier in the form "trace0",
"trace1", etc. is returned.
Ops indicates which operations are of interest, and consists of one or more of the following
letters:
r Invoke command whenever key is read. Both read and write traces are temporarily disabled
when command is executed.
w Invoke command whenever key is written. Both read and write traces are temporarily
disabled when command is executed.
c Invoke command whenever key is created.
u Invoke command whenever key is unset. Data fields are typically unset with the unset
command. Data fields are also unset when the tree is released, but all traces are
disabled prior to that.
treeName trace delete traceId...
Deletes one of more traces. TraceId is the trace identifier returned by the trace create
operation.
treeName trace info traceId
Returns information about the trace traceId. TraceId is a trace identifier previously returned by
the trace create operation. It's the same information specified for the trace create operation.
It consists of the node id or tag, data field key, a string of letters indicating the operations
that are traced (it's in the same form as ops) and, the command prefix.
treeName trace names
Returns a list of identifers for all the current traces.
NOTIFY OPERATIONS
Tree objects can be shared among many clients, such as a hiertable widget. Any client can create or
delete nodes, sorting the tree, etc. You can request to be notified whenever these events occur. Notify
events cause Tcl commands to be executed whenever the tree structure is changed.
Notifications are handled by the notify operation. The general form is treeName notify operation
?arg?... Both operation and its arguments determine the exact behavior of the command. The operations
available for events are listed below.
treeName notify create ?switches? command ?args?...
Creates a notifier for the tree. A notify identifier in the form "notify0", "notify1", etc. is
returned.
Command and args are saved and invoked whenever the tree structure is changed (according to
switches). Two arguments are appended to command and args before it's invoked: the id of the node
and a string representing the type of event that occured. One of more switches can be set to
indicate the events that are of interest. The valid switches are as follows:
-create Invoke command whenever a new node has been added.
-delete Invoke command whenever a node has been deleted.
-move Invoke command whenever a node has been moved.
-sort Invoke command whenever the tree has been sorted and reordered.
-relabel Invoke command whenever a node has been relabeled.
-allevents
Invoke command whenever any of the above events occur.
-whenidle When an event occurs don't invoke command immediately, but queue it to be run the next
time the event loop is entered and there are no events to process. If subsequent events
occur before the event loop is entered, command will still be invoked only once.
treeName notify delete notifyId
Deletes one or more notifiers from the tree. NotifyId is the notifier identifier returned by the
notify create operation.
treeName notify info notifyId
Returns information about the notify event notifyId. NotifyId is a notify identifier previously
returned by the notify create operation. It's the same information specified for the notify
create operation. It consists of the notify id, a sublist of event flags (it's in the same form
as flags) and, the command prefix.
treeName notify names
Returns a list of identifers for all the current notifiers.
C LANGUAGE API
Blt_TreeApply, Blt_TreeApplyBFS, Blt_TreeApplyDFS, Blt_TreeChangeRoot, Blt_TreeCreate,
Blt_TreeCreateEventHandler, Blt_TreeCreateNode, Blt_TreeCreateTrace, Blt_TreeDeleteEventHandler,
Blt_TreeDeleteNode, Blt_TreeDeleteTrace, Blt_TreeExists, Blt_TreeFindChild, Blt_TreeFirstChild,
Blt_TreeFirstKey, Blt_TreeGetNode, Blt_TreeGetToken, Blt_TreeGetValue, Blt_TreeIsAncestor,
Blt_TreeIsBefore, Blt_TreeIsLeaf, Blt_TreeLastChild, Blt_TreeMoveNode, Blt_TreeName, Blt_TreeNextKey,
Blt_TreeNextNode, Blt_TreeNextSibling, Blt_TreeNodeDegree, Blt_TreeNodeDepth, Blt_TreeNodeId,
Blt_TreeNodeLabel, Blt_TreeNodeParent, Blt_TreePrevNode, Blt_TreePrevSibling, Blt_TreeRelabelNode,
Blt_TreeReleaseToken, Blt_TreeRootNode, Blt_TreeSetValue, Blt_TreeSize, Blt_TreeSortNode, and
Blt_TreeUnsetValue.
KEYWORDS
tree, hiertable, widget
BLT 2.4 blt::tree(3)