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'\"
'\" Copyright 1991-1997 by Lucent Technologies, Inc.
'\"
'\" Permission to use, copy, modify, and distribute this software and its
'\" documentation for any purpose and without fee is hereby granted, provided
'\" that the above copyright notice appear in all copies and that both that the
'\" copyright notice and warranty disclaimer appear in supporting documentation,
'\" and that the names of Lucent Technologies any of their entities not be used
'\" in advertising or publicity pertaining to distribution of the software
'\" without specific, written prior permission.
'\"
'\" Lucent Technologies disclaims all warranties with regard to this software,
'\" including all implied warranties of merchantability and fitness.  In no event
'\" shall Lucent Technologies be liable for any special, indirect or
'\" consequential damages or any damages whatsoever resulting from loss of use,
'\" data or profits, whether in an action of contract, negligence or other
'\" tortuous action, arising out of or in connection with the use or performance
'\" of this software.  
'\"
'\" Tree command created by George Howlett.
'\" Extensive cleanups and enhancements by Peter MacDonald.
'\"
.so man.macros
.TH tree n BLT_VERSION BLT "BLT Built-In Commands"
.BS
'\" Note:  do not modify the .SH NAME line immediately below!
.SH NAME
tree \-  Create and manage tree data objects.
.SH SYNOPSIS
\fBtree create\fR  ?\fB-fixed\fR? ?\fB-dictset\fR? ?\fB-keyhash\fR \fIN\fR? ?\fItreeName\fR?
.sp
\fBtree destroy\fR \fItreeName\fR...
.sp
\fBtree names\fR ?\fIpattern\fR?
.sp
\fBtree op\fR \fIsubcmd\fR ?\fIsubsubcmd ...\fR? \fItreeName\fR ?\fIarg arg ...\fR?
.BE
.SH DESCRIPTION
The \fBtree command\fR is used to create, destroy, and
provide Tcl access to a \fBtree object\fR.
A \fBtree object\fR
is an ordered tree of nodes where each node can have
data key-values, tags and a label.
The \fBtreeview\fR widget uses a \fBtree object\fR.

.SH INTRODUCTION

Tree provides Tcl with a rich API for managing complex data structures.
Here is a simple example.
.PP
.CS
 set t [tree create]
 set id [$t insert 0]
 $t set $id X 2
 set n [$t get $id X]

 # Create a node with label
 $t insert 0 -label A
 $t set 0->A    X 1
 set n [$t get 0->A X]
.CE
.PP
Labels provide convenient \fB->\fR indexing relative a starting node.
.PP
Nodes may also be created with initial data values.
.PP
.CS
 $t insert 0 -label A -data {X 1   Y "a 1 b 2"}
 $t incr  0->A X 3
 $t set   0->A Y(a) 4
.CE
.PP
Note round braces are used to access sub-values in a \fBdict-array\fR.
See the section
.SB "DICT-ARRAYS"
below for details.
.CE
.SH SYNTAX
.TP
\fBtree create\fR ?\fB-fixed\fR? ?\fB-dictset\fR? ?\fB-keyhash\fR \fIN\fR? ?\fItreeName\fR?
Creates a new tree object.  The name of the new tree is returned
and a Tcl command is created.
If no \fItreeName\fR argument is present, then the name of the tree is
automatically generated in the form "\fBtree0\fR", "\fBtree1\fR",
etc relative to the current namespace.
A tree name (if given) can not start with a dash.
Tree names containing the substring "\fB#auto\fR" will
be replaced with a generated identifier.  For example, the
name \fBdata#auto\fR will translate to \fBdatatree0\fR.
Note that when
the Tcl command is deleted the \fBtree object\fR also gets freed.
.sp
Newly created trees always contain a single root node with id \fB0\fR
that can not be deleted.
.sp
Switches for \fBcreate\fR are listed below:
.RS
.TP 1i
\fB\-fixed\fR
Make \fBinsert\fR automatically set the \fB\-fixed\fR flag.
This will disallow later setting of keys not given
as \fI\-data\fR to the insert.  This includes dict-array keys.
See the \fBfixed\fR sub-command.
.TP 1i
\fB\-dictset\fR
Define that any update of an \fBarray\fR field will coerce the
array object to a dict object.
a dict will preserve order of sub-field keys on update.
See the \fBdictset\fR sub-command.
.TP 1i
\fB\-keyhash\fR \fIsize\fR
Define the size beyond which node key storage starts using
a hash (the default is 21 keys).  Normally
small numbers of keys are stored as a list.  But once more than
\fIsize\fR keys are added to a node, key storage converts to a hash.
This affects the order of key iteration (eg. for \fBget\fR/\fBnames\fR/\fBvalues\fR).
A list will iterate in the order in which keys were added,  
whereas the order of a hash is undetermined.
For large numbers of
ordered keys, specify a really large \fIsize\fR (eg. 1000000).
.RE

.TP
\fBtree destroy\fR \fItreeName\fR...
Releases one of more trees.  The Tcl command associated with
\fItreeName\fR is also removed.  Trees are reference counted.  The
internal tree data object isn't destroyed until no one else is using
the tree.
.TP
\fBtree names\fR ?\fIpattern\fR?
Returns the names of all tree objects.  if a \fIpattern\fR argument
is given, then the only those trees whose name matches pattern will
be listed.
.TP
\fBtree op\fR \fIsubcmd\fR ?\fIsubsubcmd ...\fR? \fItreeName\fR ?\fIarg arg ...\fR?
Provide direct calls to sub-commands, without going through the object command.
Aside from self documentating,
it allows wize to provide support checked tree calls.
.SH NODE IDS AND TAGS
Nodes in a tree object may be referenced by id or by tag.
Each node has a unique serial number or id that is assigned to it
at creation. The id of an node never changes or is reused
unless all nodes in a tree are delete.
.PP
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 but
can not start with
an integer.  For example, "\fBx123\fR" is valid, but "\fB123x\fR"
is not.  The same tag may be associated with one
or multiple nodes (ranges or \fItagnode\fR).
Ranges are commonly used to group nodes in various interesting ways.
.PP
Commands that take a \fItagnode\fR can operate on ranges and
will accept either a tag or a list of zero or more integer node numbers.
A node-list may contain only integers, and can not have leading spaces.
Node-lists simplify the use of iterating commands because
it avoids excessive use of \fBeval\fR.
.PP
There are four built-in or psuedo tags:
.RS
.TP 1i
\fBall\fR 
Applies to every node in the tree.
.TP 1i
\fBnonroot\fR
Applies to every node in the tree except the root node.
.TP 1i
\fBrootchildren\fR
Applies to every node in the tree whose parent is the root node.
.TP 1i
\fBroot\fR
Managed automatically by the tree object, \fBroot\fR specifies the node
that is currently set as the root node for the tree.
.RE
.PP
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 \fInode\fR is used below to indicate that an argument specifies
either an id or a tag that selects a single node.
A \fItagnode\fR is either a tag that selects a group of
nodes, or it's a list of zero or more integer node numbers.
Many tree commands only operate on a single node at a
time; if \fInode\fR is specified in a way that names multiple items, then
an error "refers to more than one node" is generated.
.SH NODE MODIFIERS
You can also specify node in relation to another node by appending one
or more modifiers to the node id or tag after \fB->\fR.
A modifier refers to a node
in relation to the specified node.  For example, 
"\fBroot->firstchild\fR"
selects the first subtree of the root node.
.PP
The following modifiers are available:
.RS
.TP 1i
\fBfirstchild\fR 
Selects the first child of the node.  
.TP 1i
\fBlastchild\fR 
Selects the last child of the node.  
.TP 1i
\fBnextnode\fR 
Selects the next node in preorder to the node.  
.TP 1i
\fBnextsibling\fR 
Selects the next sibling of the node.  
.TP 1i
\fBparentnode\fR 
Selects the parent of the node.  
.TP 1i
\fBprevnode\fR 
Selects the previous node in preorder to the node.  
.TP 1i
\fBprevsibling\fR 
Selects the previous sibling of the node.  
.TP 1i
\fBmaxnode\fR 
The maximum node number.
.TP 1i
"\fIlabel\fR"
.TP 1i
\'\fIlabel\fR'
.TP 1i
\fIlabel\fR
Selects the child node whose label is \fIlabel\fR.  Enclosing \fIlabel\fR in 
quotes (double or single) supports labels with embedded spaces and
prevents matching reserved words (eg. a node labeled "parentnode").
If mulitiple child nodes
have the same label, the first matching node is used.
.RE
.PP
It's an error if the node can't be found.  For example,
\fBlastchild\fR and \fBfirstchild\fR will generate errors if the node
has no children.  The exception to this is the \fBindex\fR operation which
returns -1, allowing you to test if a modifier is valid.
.SH TREE OPERATIONS
Once you create a tree object, you can use its Tcl command 
to query or modify it.  The
general form is
.DS
\fItreeName\fR \fIoperation\fR ?\fIarg\fR?...
.DE
Both \fIoperation\fR and its arguments determine the exact behavior of
the command.  The operations available for trees are listed below.
.TP
\fItreeName\fR \fBancestor\fR \fInode1\fR \fInode2\fR
Returns the mutual ancestor of the two nodes \fInode1\fR and
\fInode2\fR.  The ancestor can be one of the two nodes.  For example,
if \fInode1\fR and \fInode2\fR are the same nodes, their ancestor is
\fInode1\fR.
.TP
\fItreeName\fR \fBappend\fR \fInode key\fR \fIstring\fR ?\fIstring ...\fR?
Append one or more strings to node/key value.
.TP
\fItreeName\fR \fBappendi\fR \fItagnode key\fR \fIstring\fR ?\fIstring ...\fR?
The same as \fBappend\fR but accepts a multi-node tag and an
undefined key will be initialized to {}.  Returns the number of nodes
updated.
.TP
\fItreeName\fR \fBapply\fR \fInode\fR ?\fIswitches\fR?
Runs commands for all nodes matching the criteria given by
\fIswitches\fR for the subtree designated by \fInode\fR.  By default
all nodes match, but you can set switches to narrow the match.  This
operation differs from \fBfind\fR 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.
.sp
The \fB\-exact\fR, \fB\-glob\fR, 
and \fB\-regexp\fR 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 \fB\-key\fR switch is
used, it designates the data field to be matched.  
.sp
The valid switches are listed
below:
.RS
.TP 1i
\fB\-depth\fR \fInumber\fR
Descend at most \fInumber\fR (a non-negative integer) levels
If \fInumber\fR is \fB1\fR this means only apply the tests
to the children of \fInode\fR.
.TP 1i
\fB\-exact\fR \fIstring\fR
Matches each node using \fIstring\fR.  The node must match \fIstring\fR
exactly.
.TP 1i
\fB\-glob\fR \fIstring\fR
Test each node to \fIstring\fR using global pattern
matching.  Matching is done in a fashion similar to that used by
\fBstring match\fR.
.TP 1i
\fB\-invert\fR
Invert the results of the pattern matching of \fB-name\fR.
.TP 1i
\fB\-isleaf\fR
Only test nodes with no children.
.TP 1i
\fB\-istree\fR
Only test nodes with children.
.TP 1i
\fB\-key\fR \fIkey\fR
.TP 1i
\fB\-keyglob\fR \fIkey\fR
.TP 1i
\fB\-keyregexp\fR \fIkey\fR
.TP 1i
\fB\-keyexact\fR \fIkey\fR
If pattern matching is selected (using the \fB\-exact\fR,
\fB\-glob\fR, or \fB\-regexp\fR switches), compare the values of the
data field keyed by \fIkey\fR instead of the node's label.  If no
pattern matching switches are set, then any node with this data key
will match.  The field names may also be patterns using \fB-keyglob\fR, etc.
.TP 1i
\fB\-nocase\fR
Ignore case when matching patterns.
.TP 1i
\fB\-precommand\fR \fIcommand\fR
Invoke \fIcommand\fR for each matching node.  Before \fIcommand\fR is
invoked, the id of the node is appended.  You can control 
processing by the return value of \fIcommand\fR.  If \fIcommand\fR 
generates an error, processing stops and the \fBfind\fR operation 
returns an error.  But if \fIcommand\fR returns \fBbreak\fR, then 
processing stops, no error is generated.  If \fIcommand\fR returns 
\fBcontinue\fR, then processing
stops on that subtree and continues on the next.
.TP 1i
\fB\-postcommand\fR \fIcommand\fR
Invoke \fIcommand\fR for each matching node.  Before \fIcommand\fR is
invoked, the id of the node is appended.  You can control 
processing by the return value of \fIcommand\fR.  If \fIcommand\fR 
generates an error, processing stops and the \fBfind\fR operation 
returns an error.  But if \fIcommand\fR returns \fBbreak\fR, then 
processing stops, no error is generated.  If \fIcommand\fR returns 
\fBcontinue\fR, then processing
stops on that subtree and continues on the next.
.TP 1i
\fB\-regexp\fR \fIstring\fR
Test each node using \fIstring\fR as a regular expression pattern.
.TP 1i
\fB\-tag\fR \fIstring\fR
Only test nodes that have the tag \fIstring\fR.
.TP 1i
\fB\-usepath\fR
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 label.  The default is to compare only the node label.
.RE
.TP
\fItreeName\fR \fBattach\fR ?\fB-notags\fR? ?\fItreeObject\fR?
Queries or
attaches to an existing tree object \fItreeObject\fR.  This is primarly
used where the tree object was previously created via the C API (eg.
via TreeView).  The current
tree associated with \fItreeName\fR is discarded.  In addition, the
current set of tags, notifier events, and traces are removed.
If \fB-notags\fR is given, tags will not be shared.
.TP
\fItreeName\fR \fBchildren\fR  ?\fB-labels\fR? \fInode\fR ?\fIfirst\fR? ?\fIlast\fR?
Returns a list of children for \fInode\fR.  If \fInode\fR is a leaf,
then an empty string is returned.  If \fIfirst\fR and/or \fIlast\fR
are given they are the integer index of the children to display.
If the \fB-labels\fR option is used,
labels are returned instead of the nodes.
.TP
\fItreeName\fR \fBcopy\fR \fIsrcNode\fR ?\fIdestTree\fR? \fIparentNode\fR ?\fIswitches\fR?
Copies \fIsrcNode\fR into \fIparentNode\fR. Both nodes \fIsrcNode\fR and
\fIparentNode\fR must already exist. The id of the new node is
returned. You can copy from one tree to another.  If a \fIdestTree\fR 
argument is present, it indicates the name of the destination tree.  
By default both the source and destination trees are the same. The valid 
\fIswitches\fR are listed below:
.RS
.TP
\fB\-label\fR \fIstring\fR
Label \fIdestNode\fR as \fIstring\fR.  By default, \fIdestNode\fR has
the same label as \fIsrcNode\fR.
.TP
\fB\-overwrite\fR
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.
.TP
\fB\-recurse\fR
Recursively copy all the subtrees of \fIsrcNode\fR as well.  In this case,
\fIsrcNode\fR can't be an ancestor of \fIdestNode\fR as it would result
in a cyclic copy.
.TP
\fB\-reverse\fR
Reverse the direction of the copy.
.TP
\fB\-tags\fR
Copy tag information.  Normally the following node is copied: its
label and data fields.  This indicates to copy tags as well.
.RE
.TP
\fItreeName\fR \fBcreate\fR ?\fIswitches\fR?
Cause the creation of zero or more nodes.
Exactly one of \fB-num\fR, \fB-nodes\fR or \fB-path\fR is required.
This can create all nodes in a given \fB-path\fR
or efficiently populate a tree with large numbers
of nodes.
The return values is the id of the last created node (or \fB-path\fR element).
The valid flags for \fIswitches\fR are described below.
.RS
.TP 1i
\fB\-fixed\fR 
Set the fixed flag.
.TP 1i
\fB\-data\fR \fIlist\fR
Data to set in each node.
.TP 1i
\fB\-labelstart\fR \fInumber\fR
The label generated nodes is to use
a sequence number starting from \fInumber\fR.
The default is to just use the node id.
.TP 1i
\fB\-nodes\fR \fIlist\fR 
List of nodes ids to create.
The \fB\-offset\fR option can specify
a constant to add.
.TP 1i
\fB\-num\fR \fInumber\fR 
The number of nodes to create.
.TP 1i
\fB\-offset\fR \fInumber\fR 
Number to add to each element in \fB-nodes\fR.
For example, if loading sqlite rowids you should use 1.
The default is 0.
.TP 1i
\fB\-parent\fR \fInode\fR 
The \fInode\fR to insert children into.
The default is the root node.
.TP 1i
\fB\-path\fR \fIpathList\fR 
Verify that a path exists and create any missing nodes.
Uses labels in \fIpathList\fR to lookup nodes, creating
them if not found.  The id for the last
node in the path is returned (created or not).
.TP 1i
\fB\-pos\fR \fInumber\fR 
The position where to insert child nodes.
The default is -1, meaning append.
.TP 1i
\fB\-prefix\fR \fIstr\fR 
String prefix to add to each nodes label.
.TP 1i
\fB\-start\fR \fInumber\fR 
Node nuber to start from when using \fB-num\fR.  The default is 1.
.TP 1i
\fB\-tags\fR \fItagList\fR 
List of tags to add to each newly created node.
.RE
.TP
\fItreeName\fR \fBdegree\fR \fInode\fR 
Returns the number of children of \fInode\fR.
.TP
\fItreeName\fR \fBdelete\fR \fInode\fR...
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.
.TP
\fItreeName\fR \fBdepth\fR \fInode\fR 
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 \fB0\fR.
.TP
\fItreeName\fR \fBdictset\fR ?\fIbool\fR?
Get or set the dictset flag for the tree which causes any set of an
array sub-fields to force the value to type dict.
Unlike array types, dicts preserve the order of elements.
Setting this to one has the same effect as using the \fB-dictset\fR
flag at tree creation time.
.TP
\fItreeName\fR \fBdump\fR \fInode\fR ?\fIswitches\fR?
Save tree data for \fInode\fR and its descendants.
With the \fB-file\fR option, output goes to the file
\fIfileName\fR (this is unsupported in a safe interp).
With the \fB-channel\fR option, data is output to channel \fIchan\fR.
If neither option is given, the dump is returned as data.
.sp
The subtree designated by \fInode\fR is
traversed to obtain the following information for each node: 1) the node's
path relative to \fInode\fR, 2) a sublist key value pairs
representing the node's data fields, and 3) a sublist of tags.  
and 4) the label
This list returned can be used
later to copy or restore the tree with the \fBrestore\fR operation.
.sp
The valid \fIswitches\fR are listed below.
.RS
.TP
\fB\-channel \fIchan\fR
Obtain data from from the given channel \fIchan\fR.
The channel is not closed afterwards.
.TP
\fB\-file \fIfileName\fR
Obtain data from from the file.
\fIfileName\fR.  This options is unsupported in a safe interp.
.TP
\fB\-keys \fIlist\fR
A list of patterns of matching keys to be dumped.
.TP
\fB\-skipkeys \fIlist\fR
A list of patterns of matching keys not to be dumped.
.TP
\fB\-tag \fIpattern\fR
A pattern match for tags to include in a node dump.
.TP
\fB\-skiptag \fIpattern\fR
A pattern match for tags to not include in a node dump.
.TP
\fB\-notags\fR
Do not restore any tags
.TP
\fB\-nopath\fR
To save space, do not dump the full path for each node.
Instead output periods for all but the last path element.
Full paths are used only for partial restores.
.RE
.TP
\fItreeName\fR \fBexists\fR \fInode\fR ?\fIkey\fR?
Indicates if \fInode\fR exists in the tree.  If a \fIkey\fR argument
is present then the command also indicates if the named data field 
exists.
.TP
\fItreeName\fR \fBfind\fR ?\fIswitches\fR?
Finds for all nodes matching the criteria given by \fIswitches\fR 
for the subtree designated by \fInode\fR.  A list of the selected 
nodes is returned.  By default all nodes match, but you can set
switches to narrow the match.
.sp
The \fB\-exact\fR, \fB\-glob\fR, 
and \fB\-regexp\fR switches indicate what kind of pattern matching
to perform for \fB-name\fR.  By default the pattern will be compared
with the node label.  If the \fB\-key\fR switch is
used, it designates the data field to be matched.  
.sp
The order in 
which the nodes are traversed is controlled by the  \fB\-order\fR switch.
The possible orderings are \fBpreorder\fR, \fBpostorder\fR, \fBinorder\fR, 
and \fBbreadthfirst\fR.  The default is \fBpreorder\fR.
.sp
The valid switches are listed
below:
.RS 
.TP 1i
\fB\-addtag\fR \fIstring\fR 
Add the tag \fIstring\fR to each selected node.  
The tag will be created even if no nodes are tagged.
.TP 1i
\fB\-column\fR \fIkey\fR
Use value with field given by \fIkey\fR.
Like the \fBtreeview find -column\fR option,
this key may contain an array referrence.
.TP 1i
\fB\-cmdargs\fR \fIcolumns\fR
Specify columns whose values are to be appended to \fB\-command\fR.
.TP 1i
\fB\-command\fR \fIcommand\fR
Invoke \fIcommand\fR for each matching node.  Before \fIcommand\fR is
invoked, the id of the node is appended.  You can control 
processing by the return value of \fIcommand\fR.  If \fIcommand\fR 
generates an error, processing stops and the \fBfind\fR operation 
returns an error.  But if \fIcommand\fR returns \fBbreak\fR, then 
processing stops, no error is generated.  If \fIcommand\fR returns 
\fBcontinue\fR, then processing
stops on that subtree and continues on the next.
If \fIcommand\fR returns \fBreturn\fR, then the returned integer
is used to indicate 1 for match or 0 for mismatch.
.TP 1i
\fB\-count\fR
Just return the number of matches.
.TP 1i
\fB\-depth\fR \fInumber\fR
Include only nodes with level equal to \fInumber\fR.
.TP 1i
\fB\-exact\fR
Matches each node exactly.
.TP 1i
\fB\-exec\fR \fIscript\fR
Specifies a Tcl script to be evaluated for each matching node.
If \fB-var\fR was also specified, that variable is set with the value of
the node id before each evaluation.  Otherwise,
percent sustitutions are performed: note this is much
less efficient than using either \fB-var\fR or \fB-command\fR
.sp
The result of each eval gets appended to the return list, unless
the script issues a CONTINUE, in which case that node is skipped.
.sp
The available percent substitutions on \fIstring\fR are:
.RS 
.TP 5
\fB%#\fR
The id of the node.
.TP 5
\fB%W\fR
The pathname of the tree.
.TP 5
\fB%p\fR
The label of the node.
.TP 5
\fB%P\fR
The full pathname of the node.
.TP 5
\fB%R\fR
The -> delimited path from root, eg. "root->able->baker->charlie"
.TP 5
\fB%r\fR
The -> delimited path from 0, eg. "0->able->baker->charlie"
.TP 5
\fB%T\fR
The dot delimited tag path eg. ".able.baker.charlie"
.TP 5
\fB%V\fR
The value if using \fB-key\fR or the label otherwise.
.TP 5
\fB%D\fR
The data for the node, ie. like that returned from \fBget\fR.
.TP 5
\fB%%\fR
Translates to a single percent.
.RE
.TP 1i
\fB\-glob\fR
Test each node using global pattern
matching.  Matching is done in a fashion similar to that used by the
\fBstring match\fR.
.TP 1i
\fB\-invert\fR
Invert the pattern matching of \fB-name\fR.
.TP 1i
\fB\-isarray\fR
Only test nodes where the specified \fB-key\fR value
is an array.  Can not be used with \fB-name\fR.
The \fB-invert\fR flag will invert the meaning of the
check.  Note that this will attempt to convert the key value in
each traversed node into an array type.
.TP 1i
\fB\-isempty\fR
Only match nodes where the specified \fB-column\fR key value
was unset.
.TP 1i
\fB\-isfixed\fR
Only test nodes that have used \fBfixed 1\fR.
.TP 1i
\fB\-isleaf\fR
Only test nodes with no children.
.TP 1i
\fB\-isnotfixed\fR
Only test nodes that have not used \fBfixed 1\fR.
.TP 1i
\fB\-istree\fR
Only test nodes with children.
.TP 1i
\fB\-keycount\fR \fInum\fR
Only test if number of keys is equal to \fInum\fR.
.TP 1i
\fB\-key\fR \fIkey\fR
.TP 1i
\fB\-keyglob\fR \fIkey\fR
.TP 1i
\fB\-keyregexp\fR \fIkey\fR
.TP 1i
\fB\-keyexact\fR \fIkey\fR
Compare the values of the data field keyed by \fIkey\fR instead of 
the node's label. If no \fB\-name\fR pattern is used 
then any node with this data key will match.
The key names may also be patterns using \fB-keyglob\fR, etc.
.TP 1i
\fB\-limit\fR \fInumber\fR
Stop processing after \fInumber\fR (a positive integer) matches. 
.TP 1i
\fB\-maxdepth\fR \fInumber\fR
Include only nodes at level \fInumber\fR or less.
.TP 1i
\fB\-mindepth\fR \fInumber\fR
Include only nodes at level \fInumber\fR or greater.
.TP 1i
\fB\-name\fR \fIstring\fR
The name to use for pattern matching.
.TP 1i
\fB\-nocase\fR
Ignore case when matching patterns.
.TP 1i
\fB\-nodes \fItagnode\fR
Search only in \fItagnode\fR, which is either a tag
or a list of nodes ids.  This makes possible nested searches.
Note this option is incompatible with
\fB-top\fR and \fB-notop\fR.
.TP 1i
\fB\-notop\fR
Exclude the \fB-top\fR or starting node.
.TP 1i
\fB\-order\fR \fIstring\fR 
Traverse the tree and process nodes according to \fIstring\fR. \fIString\fR
can be one of the following:
.RS
.TP 1i
\fBbreadthfirst\fR 
Process the node and the subtrees at each sucessive level. Each node
on a level is processed before going to the next level.
.TP 1i
\fBinorder\fR 
Recursively process the nodes of the first subtree, the node itself,
and any the remaining subtrees.
.TP 1i
\fBpostorder\fR 
Recursively process all subtrees before the node.
.TP 1i
\fBpreorder\fR 
Recursively process the node first, then any subtrees (default).
.RE
.TP 1i
\fB\-usepath\fR
Use the node's full path when doing the comparison.
The default is to compare only the node label.
.TP 1i
\fB\-regexp\fR
Test each node using regular expression pattern matching.
.TP 1i
\fB\-reldepth\fR
Change the meaning of \fB\-depth\fR, \fB\-mindepth\fR and \fB\-maxdepth\fR
to be relative to the \fB\-top\fR node.
.TP 1i
\fB\-return \fIkey\fR
Return the value of the given \fIkey\fR, or the empty string if none.
If the given \fIkey\fR is the empty string, the node label will be returned.
If no value was found and the given \fIkey\fR starts with a percent
returns the sustitution as per \fB-exec\fR.  Note that a percent
substitution longer than 2 chars will append values as list elements.
.TP 1i
\fB\-strict\fR
Generate an error if a given key value is unset when using \fB-return\fR.
.TP 1i
\fB\-top \fInode\fR
Search is only at \fInode\fR and it's descendants.
The default is the root node.
.TP 1i
\fB\-var \fIvariable\fR
A variable to set with the node id before each iteration of the \fB-exec\fR
script.
.TP 1i
\fB\-withouttag\fR \fIstring\fR
Only test nodes that don't have the tag \fIstring\fR.
.TP 1i
\fB\-withtag\fR \fIstring\fR
Only test nodes that have the tag \fIstring\fR.
.RE
.TP
\fItreeName\fR \fBfindchild\fR \fInode\fR \fIlabel\fR
Searches for a child node \fIlabel\fR in \fInode\fR.  The id of the 
child node is returned if found.  Otherwise \fB-1\fR is returned.
This is the same as using \fBindex \fInode->label\fR.
.TP
\fItreeName\fR \fBfirstchild\fR \fInode\fR 
Returns the id of the first child in the \fInode\fR's list
of subtrees.  If \fInode\fR is a leaf (has no children), 
then \fB-1\fR is returned.
.TP
\fItreeName\fR \fBfixed\fR \fInode\fR ?\fIisfixed\fR?
Get or set the fixed key-fields flag for a node.
New key-fields can be added to a node only if fixed is 0 (the default) 
If \fInode\fR is given as an empty string, operates on the tree flag.
Note that copied and restored nodes do not preserve the fixed state.
.TP
\fItreeName\fR \fBforeach\fR \fIvar tagnode script\fR
Provides a \fBforeach\fR loop for tree.  For
each node in \fItagnode\fR the node-id is assigned to \fIvar\fR and then
\fIscript\fR is evaluated. The \fItagnode\fR is either a tag or a list of
nodes as described in the section
.SB NODE IDS AND TAGS
above.
.TP
\fItreeName\fR \fBget\fR \fInode\fR ?\fIkey\fR? ?\fIdefaultValue\fR?
Returns a list of key-value pairs of data for \fInode\fR.  If \fIkey\fR
is present, then only the value for that particular data field is
returned.  It's normally an error if \fInode\fR does not contain the
data field \fIkey\fR.  But if you provide a \fIdefaultValue\fR
argument, this value is returned instead (\fInode\fR will still not
contain \fIkey\fR).  This feature can be used to access a data field of
\fInode\fR without first testing if it exists.  This operation may
trigger \fBread\fR data traces.
.TP
\fItreeName\fR \fBincr\fR \fInode key\fR ?\fIamount\fR?
Increment value by 1 or given \fIamount\fR and return the value.
The incr operation normally tries to use integers,
but uses doubles when one of
value or \fIamount\fR is a double.
.TP
\fItreeName\fR \fBincri\fR \fItagnode key\fR ?\fIamount\fR?
The same as \fBincr\fR but accepts a multi-node tag and an
undefined key will be initialized to 0.  Returns the number of nodes
updated.
.TP
\fItreeName\fR \fBindex\fR \fInode\fR
Returns the id of \fInode\fR.  In addition
to standard node id form,
\fInode\fR can also be a path (a list of labels from the root) as returned
by the \fBpath\fR command.
If \fInode\fR is invalid, then \fB-1\fR is returned.
.TP
\fItreeName\fR \fBinsert\fR \fIparent\fR ?\fIswitches\fR? 
Inserts a new node into parent node \fIparent\fR.  
The id of the new node is returned.
The following switches 
are available:
.RS
.TP 1i
\fB\-after\fR \fIchild\fR 
Position \fInode\fR after \fIchild\fR.  The node \fIchild\fR must be a 
child of \fIparent\fR.
.TP 1i
\fB\-before\fR \fIchild\fR 
Position \fInode\fR before \fIchild\fR.  The node \fIchild\fR must be a 
child of \fIparent\fR.
.TP 1i
\fB\-data\fR \fIdataList\fR
Sets the value for each data field in \fIdataList\fR for the 
new node. \fIDataList\fR is a list of key-value pairs.
May not be used in conjuction with \fB-names\fR or  \fB-values\fR.
.TP 1i
\fB\-fixed\fR \fIbool\fR
If \fIbool\fR is 1, set \fBfixed\fR field mode after initializing
the key/value pairs from \fB-data\fR.
This disallows creation of new key fields
after the node is created.
If not given, the tree default for fixed is used.
.TP 1i
\fB\-label\fR \fIstring\fR 
Designates the labels of the node as \fIstring\fR.  By default, nodes
are labeled as \fB0\fR, \fB1\fR, etc.
.TP 1i
\fB\-names\fR \fInameList\fR
The names for the data fields.  This must have the same length as
\fB-values\fR, and may not be used in conjuction with \fB-data\fR.
.TP 1i
\fB\-node\fR \fIid\fR 
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.
.TP 1i
\fB\-pos\fR \fInumber\fR 
Inserts the node into \fIparent\fR's list of children at 
position \fInumber\fR.  The default is to append.
.TP 1i
\fB\-pretags\fR \fItagList\fR
Adds each tag in \fItagList\fR to the new node, before
data is added.  Unlike \fB-tags\fR, traces on these tags
will fire on key data during the insert.
.TP 1i
\fB\-tags\fR \fItagList\fR
Adds each tag in \fItagList\fR to the new node. \fITagList\fR is a list
of tags, so be careful if a tag has embedded space.
.TP 1i
\fB\-values\fR \fIvalueList\fR
The values for the data fields.  This must have the same length as
\fB-names\fR, and may not be used in conjuction with \fB-data\fR.
.RE
.TP
\fItreeName\fR \fBis\fR \fIproperty\fR \fIargs\fR  
Indicates the property of a node. Both \fIproperty\fR and \fIargs\fR
determine the property being tested.  Returns \fB1\fR if true and
\fB0\fR otherwise.  The following \fIproperty\fR and \fIargs\fR 
are valid:
.RS
.TP 1i
\fBancestor\fR \fInode1\fR \fInode2\fR
Indicates if \fInode1\fR is an ancestor of \fInode2\fR. 
.TP 1i
\fBbefore\fR \fInode1\fR \fInode2\fR
Indicates if \fInode1\fR is before \fInode2\fR in depth first traversal. 
.TP 1i
\fBleaf\fR \fInode\fR
Indicates if \fInode\fR is a leaf (it has no subtrees).
.TP 1i
\fBroot\fR \fInode\fR
Indicates if \fInode\fR is the designated root.  This can be changed
by the \fBroot\fR operation.
.RE
.TP
\fItreeName\fR \fBismodified\fR ?\fInodeOrTag\fR? ?\fIisflag\fR?
Get or set modified state for the tree or nodes.
With no args returns modified state for tree.
With one args returns modified state for a node.
With two args set modified state for one or more nodes.
In the last case, where ?\fInodeOrTag\fR? is the tag \fBall\fR,
the state for the tree is also set.
.sp
Newly created nodes
are always considered to be modified until explicitly
cleared.  After clearing, subsequent updates to keys or tags
will toggle the node (and tree) modified again.
.TP
\fItreeName\fR \fBisset\fR \fInode\fR \fIkey\fR
Return 1 if key is set in node.
.TP
\fItreeName\fR \fBkeys\fR \fInode\fR ?\fItagnode ...\fR?
Return list of unique keys for all of the given nodes in \fItagnode\fR.
Keys are in no particular order.
Accepts nodes and tags or all.  See also \fBnames\fR.
.TP
\fItreeName\fR \fBlabel\fR \fInode\fR ?\fInewLabel\fR?
Returns the label of the node designated by \fInode\fR.  If \fInewLabel\fR
is present, the node is relabeled using it as the new label.
.TP
\fItreeName\fR \fBlappend\fR \fInode key\fR \fIvalue\fR ?\fIvalue ...\fR?
Append one or more list values to node/key value.
.TP
\fItreeName\fR \fBlappendi\fR \fItagnode key\fR \fIvalue\fR ?\fIvalue ...\fR?
The same as \fBlappend\fR but accepts a multi-node tag and an
undefined key will be initialized to {}.  Returns the number of nodes
updated.
.TP
\fItreeName\fR \fBlastchild\fR \fInode\fR
Returns the id of the last child in the \fInode\fR's list
of subtrees.  If \fInode\fR is a leaf (has no children), 
then \fB-1\fR is returned.
.TP
\fItreeName\fR \fBmodify\fR \fItagnode\fR \fIkey value\fR ?\fIkey value\fR...?
Update one or more fields in one or more nodes in \fItagnode\fR.
As with \fBset\fR, \fInode\fR
can be a tag referring to multiple nodes.
This is identical to \fBset\fR, except an error is thrown if
any of the key fields do not exist.
Despite the error, all nodes that do have said fields get updated.
For modifying a single node, see \fBupdate\fR.
.TP
\fItreeName\fR \fBmove\fR \fInode\fR \fInewParent\fR ?\fIswitches\fR?
Moves \fInode\fR into \fInewParent\fR. \fINode\fR is appended to the
list children of \fInewParent\fR.  \fINode\fR can not be an ancestor
of \fInewParent\fR.  The valid flags for \fIswitches\fR are described below.
.RS
.TP 1i
\fB\-after\fR \fIchild\fR 
Position \fInode\fR after \fIchild\fR.  The node \fIchild\fR must be a 
child of \fInewParent\fR.
.TP 1i
\fB\-before\fR \fIchild\fR 
Position \fInode\fR before \fIchild\fR.  The node \fIchild\fR must be a 
child of \fInewParent\fR.
.TP 1i
\fB\-pos\fR \fInumber\fR 
Inserts \fInode\fR into \fIparent\fR's list of children at 
position \fInumber\fR. The default is -1 to append the node.
.RE
.TP
\fItreeName\fR \fBnames\fR \fInode\fR ?\fIkey\fR? ?\fIpattern\fR?
Return key names for \fInode\fR, in the order defined (if possible).
If a key is given, attempts to return ARRAY fields (see DICT-ARRAYS).
If a pattern is given, the array keys are limited
to those matching the glob pattern.
An error is thrown if the convert to array fails (ie. list-length is odd).
The \fBtype\fR command can be used to query the type.
See also \fBvalues\fR.
.TP
\fItreeName\fR \fBnext\fR \fInode\fR
Returns the next node from \fInode\fR in a preorder traversal.
If \fInode\fR is the last node in the tree, 
then \fB-1\fR is returned.
.TP
\fItreeName\fR \fBnextsibling\fR \fInode\fR
Returns the node representing the next subtree from \fInode\fR
in its parent's list of children.  If \fInode\fR is the last child, 
then \fB-1\fR is returned.
.TP
\fItreeName\fR \fBnodeseq\fR ?\fIstart\fR?
Get or set the \fIstart\fR sequence number for subsequent
node insertions not using \fB-node\fR.  The default is 0.
.TP
\fItreeName\fR \fBnotify\fR \fIargs\fR 
Manages notification events that indicate that the tree structure has 
been changed.
See the 
.SB "NOTIFY OPERATIONS"
section below.
.TP
\fItreeName\fR \fBoldvalue\fR ?\fInewvalue\fR?
Return the value from before the last (untraced) change operation.
This is used primarly by write traces wishing to
restore a key to it's pre-write value (eg. read-only variables).
The oldvalue is saved internally everytime a change operation occurs
to a key value by deferring its deallocation.
Changes made during node traces do not affect oldvalue.
.sp
If \fInewvalue\fR is provided, the current value of oldvalue is
discarded and replaced. This is useful really only for releasing large objects.
.TP
\fItreeName\fR \fBparent\fR \fInode\fR
Returns the parent node of \fInode\fR.  If \fInode\fR is the root
of the tree, 
then \fB-1\fR is returned.
.TP
\fItreeName\fR \fBpath\fR \fInode\fR ?\fIdelim\fR? ?\fIprefix\fR?
Returns the full path (from root) of \fInode\fR using the node labels.
If \fIdelim\fR is not specified, the result is a list.
Otherwise, the result is a string starting with \fIprefix\fR and
each element of the path separated by \fIdelim\fR.
This latter form is useful for building tags like: \fB.able.baker\fR
.TP
\fItreeName\fR \fBposition\fR  ?\fB-sort\fR? ?\fB-format\fR \fIftype\fR? \fInode\fR ?\fInode\fR ...?
Returns the position of the node(s) in its parent's list of children.
Positions are numbered from 0.
The position of the root node is always 0.
The value of \fIftype\fR is one of:
\fBposition parent-at-position id+position id+parent-at-position\fR.
.TP
\fItreeName\fR \fBprevious\fR \fInode\fR
Returns the previous node from \fInode\fR in a preorder traversal.
If \fInode\fR is the root of the tree, 
then \fB-1\fR is returned.
.TP
\fItreeName\fR \fBprevsibling\fR \fInode\fR
Returns the node representing the previous subtree from \fInode\fR
in its parent's list of children.  If \fInode\fR is the first child, 
then \fB-1\fR is returned.
.TP
\fItreeName\fR \fBrestore\fR \fInode\fR \fIswitches\fR
Performs the inverse function of the \fBdump\fR operation, restoring
nodes to the tree. The format of the input data is exactly what is 
returned by the \fBdump\fR 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, 3) a list of tags for the node, and 4) the label.
Nodes are created 
starting from \fInode\fR. Nodes can be listed in any order.  If a node's 
path describes ancestor nodes that do not already exist, they are 
automatically created.
.sp
The valid \fIswitches\fR are listed below.  Exactly one
of \fB-channel\fR,  \fB-file\fR or  \fB-data\fR must be specified.
.RS
.TP
\fB\-addtags\fR
List of tags to add to each node restored node.
Each tag will be created only if a node loaded.
.TP
\fB\-channel \fIchan\fR
Obtain data from from the given channel \fIchan\fR.
The channel is not closed afterwards.
.TP
\fB\-data \fIstring\fR
Data input is from the given \fIstring\fR.
.TP
\fB\-file \fIfileName\fR
Obtain data from from the file.
\fIfileName\fR.  This options is unsupported in a safe interp.
.TP
\fB\-keys \fIlist\fR
A list of patterns of matching keys to be restored.
.TP
\fB\-skipkeys \fIlist\fR
A list of patterns of matching keys not to be restored.
.TP
\fB\-tag \fIpattern\fR
A pattern match for tags to include in a node restore.
.TP
\fB\-skiptag \fIpattern\fR
A pattern match for tags to not include in a node restore.
.TP
\fB\-notags\fR
Do not restore any tags
.TP
\fB\-overwrite\fR
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 overwrite existing node's data fields.
.RE
.TP
\fItreeName\fR \fBroot\fR ?\fInode\fR?
Returns the id of the root node.  Normally this is node \fB0\fR.  If
a \fInode\fR 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 \fBnext\fR, \fBpath\fR,
\fBprevious\fR, etc.
.TP
\fItreeName\fR \fBset\fR \fItagnode\fR \fIkey value\fR ?\fIkey value\fR...?
Sets one or more data fields in \fInode\fR. \fItagode\fR may 
be a tag that represents several nodes and a count of the number
of nodes updated is returned.
\fIKey\fR is the
name of the data field to be set, or an array-like reference such as \fBfield(subkey)\fR.
See the
.SB "DICT-ARRAYS"
section below.  \fIValue\fR is the respective keys value.
The  \fIKey\fR  will be created if it does not exists (see \fBmodify\fR).
.sp
The set operation triggers \fBwrite\fR and \fBcreate\fR data traces.
.TP
\fItreeName\fR \fBsize\fR \fInode\fR
Returns the number of nodes in the subtree. This includes the node
and all its descendants.  The size of a leaf node is 1.
.TP
\fItreeName\fR \fBsort\fR \fInode\fR ?\fIswitches\fR? 
Return nodes in sorted order.
.RS
.TP 1i
\fB\-ascii\fR 
Compare strings using the ASCII  collation order.
.TP 1i
\fB\-command\fR \fIstring\fR
Use command \fIstring\fR as a comparison command.  To compare two
elements, evaluate a Tcl script consisting of command with the five
elements appended as additional arguments:
\fIthe tree, node1, node1, label1, label2\fR.
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.
.TP 1i
\fB\-decreasing\fR
Sort in decreasing order (largest items come first).
.TP 1i
\fB\-dictionary\fR
Compare strings using a dictionary-style comparison.  This is the same 
as \fB\-ascii\fR 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 \fB\-dictionary\fR mode, bigBoy sorts between
bigbang and bigboy, and x10y sorts between x9y and x11y.
.TP 1i
\fB\-integer\fR
Compare the nodes as integers.  
.TP 1i
\fB\-key\fR \fIstring\fR
Sort based upon the node's data field keyed by \fIstring\fR. Normally
nodes are sorted according to their label.
label.
.TP 1i
\fB\-real\fR
Compare the nodes as real numbers.
.TP 1i
\fB\-recurse\fR
Recursively sort the entire subtree rooted at \fInode\fR.
.TP 1i
\fB\-reorder\fR 
Recursively sort subtrees for each node.  \fBWarning\fR.  Unlike
the normal flat sort, where a list of nodes is returned, this will
reorder the tree.  
.TP 1i
\fB\-usepath\fR
Compare the full path of each node.  The default is to compare only the node
label.
.RE
.TP
\fItreeName\fR \fBsqlload\fR ?\fIswitches\fR? \fIdbhfile\fR \fIsqlstmt\fR
Load tree with the results of evaling the SQL in \fIsqlstmt\fR using
\fIdbhfile\fR.
The evaluated SQL creates one tree-node per row result.
The returned value is the number of rows loaded.
\fIDbhfile\fR is either an \fBsqlite3\fR database handle,
or an \fBsqlite3\fR file.
.sp
The \fBsqlload\fR command can populate a tree with 10k nodes
about 7 times faster than \fBsqlite3 eval\fR.
It also preserves NULL values
and object types (eg. int or double) used internally
by sqlite.  This eliminates later reconversion within tree.
See the
.SB "SQLLOAD EXAMPLE"
below.
.sp
The following switches are available:
.RS
.TP 1i
\fB\-addtags \fItaglist\fR
The tags in \fItaglist\fR to add to each inserted node.
Each tag will be created only if a node loaded.
.TP 1i
\fB\-fixed\fR
Set the \fBfixed\fR flag to disallow new keys after creation.
.TP 1i
\fB\-key \fIname\fR
Store the entire result in the key \fIname\fR instead
of creating one key per column.
Array notation can be used to then access column results.
This is more efficent as it initially stores just one
object per row.  Conversion to an array
is at the first array access (if that occurs).
.TP 1i
\fB\-labelcol \fIcolumn\fR
The value of \fIcolumn\fR is used as the label.
By default the label is the node id.
.TP 1i
\fB\-maprowid \fInum\fR
This option maps the node id to the rowid plus the constant \fInum\fR.
The key for \fBrowid\fR will also not be created.
This is applicable only if \fBrowid\fR is returned in the result-set
of \fIsqlstmt\fR.
If \fBrowid\fR is not in the result set, this option is ignored.
If mapping fails (because the tree already contains a requested node)
the load will abort at that point
with an error.  Note that \fInum\fR must be >= 1 since sqlite
rowids start from 0, but the root node of the tree uses the node-id 0.
.TP 1i
\fB\-max \fInum\fR
The maximum number of rows to return.  The default is 100,000.
Note that SQL queries on large tables should probably always use LIMIT.
.TP 1i
\fB\-nullvalue \fIstring\fR
Define value to use for null values.  The default is no value,
meaning do not set key if value is null.
Note this is different from the sqlite Tcl extension which uses
an empty string for NULL.
.TP 1i
\fB\-parent \fIstring\fR
The node where results are
inserted as child nodes.  The default is the tree root.
.TP 1i
\fB\-pathcol \fIcolumn\fR
Name of column containing the full path where node is to be created.
This works like \fB\-treecols\fR, but uses a singl columns.
.TP 1i
\fB\-skipcols \fIcolumns\fR
The given \fIcolumns\fR are not to be added as keys.  This is useful mostly
in conjuction with \fB-tagcol\fR, \fB-labelcol\fR, \fB-pathcol\fR.
.TP 1i
\fB\-pos \fInum\fR
Where to insert into parents list of children.
Default is -1, meaning to append.
.TP 1i
\fB\-tagcol \fIcolumn\fR
The value of \fIcolumn\fR is added as a tag.
.TP 1i
\fB\-treecols \fIcolumns\fR
Columns whose values concatenated
give the path of where node is to be created.
This works like \fB\-pathcol\fR, but uses multiple columns.
.RE
.TP
\fItreeName\fR \fBsum\fR ?\fIswitches\fR? \fItagnode key\fR ?\fIkey ...\fR?
Add values in key fields for all \fItagnode\fR and return the sum.
Values that are not doubles (or integer) are ignored.
.RS
.TP 1i
\fB\-diff\fI value\fR 
Double value difference to ignore and not do update for \fB-runtotal\fR.
This is unused when using \fB\-int\fR.
.TP 1i
\fB\-force\fR 
Force update \fB-runtotal\fR even if value was unchanged.
Normally, a check is made to avoid updating unchanged values.
.TP 1i
\fB\-int\fR 
Use and accept only integer values.
.TP 1i
\fB\-runtotal \fIkey\fR 
Place running total in the given key field (if changed).
.TP 1i
\fB\-start \fInum\fR 
The start value for the sum: default is 0.
.RE
.TP
\fItreeName\fR \fBsupdate\fR \fInode\fR \fIkey value\fR ?\fIkey value\fR...?
Like \fBupdate\fR, but uses a string comparison
to avoid writes if the value will not be changed.  This is useful primarily
for avoiding unnecessary write traces.
.TP
\fItreeName\fR \fBtag\fR \fIargs\fR
Manages tags for the tree object.
See the 
.SB "TAG OPERATIONS"
section below.
.TP
\fItreeName\fR \fBtrace\fR \fIargs\fR
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 
.SB "TRACE OPERATIONS"
section below.
.TP
\fItreeName\fR \fBtype\fR \fInode\fR \fIkey\fR
Return type of value.  This is the introspected type from the Tcl_Obj
value passed to set.
.TP
\fItreeName\fR \fBupdate\fR \fInode\fR \fIkey value\fR ?\fIkey value\fR...?
Like \fBmodify\fR, except an error is generated if a tag
is used that applies to more than one node.
.TP
\fItreeName\fR \fBunset\fR \fInode\fR \fIkey\fR...
Removes one or more data fields from \fInode\fR. \fINode\fR may 
be a tag that represents several nodes.  \fIKey\fR is the
name of the data field to be removed.  It's not an error is
\fInode\fR does not contain \fIkey\fR.
A count of the number of nodes unset is returned.
This operation may trigger \fBunset\fR data traces.
.TP
\fItreeName\fR \fBvalues\fR \fInode\fR ?\fIkey\fR? ?\fIwithnames\fR?
Return values for \fInode\fR.
The values are returned in the same order as the keys
returned from \fBnames\fR.
.sp
If a \fIkey\fR is given,
array values get returned for the \fIkey\fR value.
If \fIwithname\fR is \fBTrue\fR, then key
names are also returned with the values.  This differs from \fBget\fR
in that the result is a true Tcl list object, not an array object.
If subsequently using an array value in a list context,
this can be more efficient by
avoiding a split on string representations.
.TP
\fItreeName\fR \fBvecdump\fR \fIvector\fR \fIkey\fR ?\fItagnode\fR?
Dump key field to a vector.  With no \fItagnode\fR, dumps every node
to the 1-1 corresponding vector index.  With \fItag\fR dumps
nodes to consequetive vector elements.
.TP
\fItreeName\fR \fBvecload\fR \fIvector\fR \fIkey\fR ?\fItagnode\fR?
Loads key field from a vector.  With no \fItagnode\fR, loads every node
from the 1-1 corresponding vector index.  With \fItag\fR loads
nodes from consequetive vector elements.
.TP
\fItreeName\fR \fBwith\fR \fIvariable\fR ?\fIswitch\fR? \fItagnode script\fR
For each node in \fItagnode\fR,
evaluate the \fIscript\fR after assigning key values to
elements of the array \fIvariable\fR.
The \fB-keys\fR limits which keys may be assigned.
If \fIscript\fR completes normally,
and any of the key values change in the \fIvariable\fR, then the
updates are reflected back into the key values
(unless \fB-noupdate\fR is used).
Unsetting a variable key
will cause that change to be ignored.  New elements added to the
array variable are ignored.
.sp
Doing a \fBreturn\fR, \fBbreak\fR, or \fBcontinue\fR inside
\fIscript\fR will still cause updates to copy back, but
processing will stop and (unless \fB-break\fR is used)
the return code will become the return code to the caller.
This means that a \fBbreak\fR, \fBcontinue\fR, and
\fBreturn\fR will propagate up through
multiple nested \fBwith\fR statements to the
to an enclosing \fBforeach\fR, \fBwhile\fR, etc.
But \fB-break\fR can be used to change this, making \fBwith\fR behave more
like a \fBforeach\fR loop.
.sp
If \fB-keys\fR is not used, the list of key names will be
stored in \fIvariable(*)\fR and the node id
stored in \fIvariable(#)\fR (which could then
be overwritten by a key of that name).
By default, the array is not cleaned up before or after each execution.
However, if \fB-unset\fR is used, the array is unset at the start of each
iteration, and \fB-init\fR can be used to specify a default value.
Also, long running queries can speed up by initializing variables 
prior to the call to \fBwith\fR.
.sp
If the \fIvariable\fR name string is zero length, an simple
variables are used instead of an array,
and * and # do not get set.
Note, when not using -keys, arbitrary local variables can get overwritten.
.sp
If \fB-array\fR is used, \fBwith\fR operates on the keys of an tree array/dict
instead of the keys of the node.
.sp
Upon normal completion, the number of times \fIscript\fR
was evaluated is returned.
.sp
The valid switches are listed below:
.RS
.TP 1i
\fB-array\fR \fIkey\fR
Specifies a
single key that is to be treated as an array-dict.
The fields of the array for that one key are then used
(instead of keys from the whole node).
This changes the meaning of \fB-keys\fR and \fB-glob\fR to be the
keys of the array rather than the keys of the node.
Nodes missing the given array key will be skipped.
If a key value can not be converted to an array,
an error will occur.
.TP 1i
\fB-break\fR
Treat \fBbreak\fR and \fBcontinue\fR like \fBforeach\fR does
rather than just passing them up to the enclosing script body.
.TP 1i
\fB-init\fI value\fR
Variables specified by \fB-keys\fR are to be initialized to \fIvalue\fR
for each node where key is missing.
.TP 1i
\fB-keys\fR \fIkeylist\fR
Copy only the named keys and does not set (*).
.TP 1i
\fB-glob\fR \fIpattern\fR
Pattern to limit matching keys.  Can not be used with \fB-keys\fR.
.TP 1i
\fB-noupdate\fR
Ignore changes to array variables. This
do not copy changed variables back into tree nodes.
.TP 1i
\fB-unset\fR
Unset the array variable at the begin of each evaluation.
.RE
.RE
.SH DICT-ARRAYS
Round braces can be used to access sub-values of a key value.
In effect, this means each key value can be an array (or dict), eg.
.PP
.CS
 set t [tree create]
 set n [$t insert 0 -data {a 1   b 2   c "x 9 y 8 z 7"}]
 $t get $n;          #  a 1 b 2 c {x 9 y 8 z 7}
 $t get $n c;        #  x 9 y 8 z 7
 $t get $n c(y);     # 8
 $t update $n c(y) 8.6
 $t get $n c;        # x 9 y 8.6 z 7
 $t unset $n c(y)
 $t get $n c;        # x 9 z 7
 $t set $n d 10
 $t incr $n d
.CE
.PP
If a key value is a dict object tree will make use of it.
If not, on access it converts the value to a pure \fBarray\fR hash object.
The following example shows the type in a comment after each operation.
.PP
.CS
 set t [tree create]
 $t insert 0 -label A;
 $t set   0->A  X [dict create a 1 b 2 c 3];   # dict
 array set q { x 1 y 2 };
 $t set   0->A  Y [array get q];               # dict
 $t set   0->A  Z {m 0 n 1};                   # string
 $t incr  0->A  Z(m);                          # array
 dict size [$t get 0->A Z];                    # dict
.CE
.PP
One advantage of using a dict is that it preserves order.
See \fBdictset\fR.
.SH 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.  
.PP
Most tree operations use tags.  And several operations let you
operate on multiple nodes at once.  For example, you can use the
\fBset\fR operation with the tag \fBall\fR to set a data field in 
for all nodes in the tree.
.PP
Tags are invoked by the \fBtag\fR operation.  The
general form is
.DS
\fItreeName\fR \fBtag\fR \fIoperation\fR ?\fIarg\fR?...
.DE
Both \fIoperation\fR and its arguments determine the exact behavior of
the command.  The operations available for tags are listed below.
.TP
\fItreeName\fR \fBtag add\fR \fIstring\fR ?\fInode\fR?...
Adds the tag \fIstring\fR to zero or more nodes.
If no nodes are given, just creates the tag.
A count of the number of nodes tagged is returned.
.TP
\fItreeName\fR \fBtag delete\fR \fIstring\fR \fInode\fR...
Remove the tag \fIstring\fR from one or more nodes.  
A count of the number of nodes visited is returned.
Calling \fBtag delete\fR with a builtin tag is ignore.
.TP
\fItreeName\fR \fBtag dump\fR \fItagnode\fR ?\fIswitches\fR?
Dump the nodes specified by the tag \fItagnode\fR.
.sp
The valid \fIswitches\fR are listed below.
.RS
.TP
\fB\-keys \fIlist\fR
A list of patterns of matching keys to be dumped.
.TP
\fB\-skipkeys \fIlist\fR
A list of patterns of matching keys not to be dumped.
.TP
\fB\-tag \fIpattern\fR
A pattern match for tags to include in a node dump.
.TP
\fB\-skiptag \fIpattern\fR
A pattern match for tags to not include in a node dump.
.TP
\fB\-notags\fR
Do not dump the tags.
.TP
\fB\-nopath\fR
To save space, do not dump the full path for each node.
Instead output periods for all but the last path element.
Full paths are used only for partial restores.
.RE
.TP
\fItreeName\fR \fBtag exists\fR \fIstring\fR ?\fIid\fR?
If an \fIid\fR is given, return 1 (or 0)  if node has (or hasn't) the tag.
Otherwise, returns 1 if at least one nodes has tag \fIstring\fR.
.TP
\fItreeName\fR \fBtag forget\fR \fIstring\fR ?\fIstring\fR ...?
Removes the tag definition for one or more of \fIstring\fR.
It's not an error if the tag \fIstring\fR does not exist.
.TP
\fItreeName\fR \fBtag lookups\fR ?\fIpattern\fR?
Dump a lookup table (dictionary)
of nodes-to-tags, or tags-to-nodes if \fIpattern\fR
is given.
With no arguments, returns a pair list of nodes/tags,
for nodes that have tags.
With an argument, returns a pair list of tags/nodes.
\fBlookups\fR provides efficient bulk processing when dealing with
large numbers of nodes and/or tags.
.TP
\fItreeName\fR \fBtag names\fR ?\fB-glob\fR? ?\fB-regexp\fR? ?\fB-nocase\fR?  ?\fInode\fR? ?\fInode ...\fR?
Returns a list of tags used by the tree.  If no \fInode\fR argument
is given, returns a list of all known tags.  Otherwise, returns
the union of the tags used by all given \fInode\fR numbers.
Patterns can be used via \fB-glob\fR or \fB-regexp\fR.
If \fB-nocase\fR is used, the pattern is expected to be all lower case.
.TP
\fItreeName\fR \fBtag nodes\fR \fIstring\fR ?\fIstring ...\fR?
Returns a list of any nodes that have any of given \fIstring\fR tag.  If no node
is tagged with any of the \fIstring\fR, then an empty string is returned.
.SH TRACE OPERATIONS
Data fields can be traced much like tracing Tcl
variables.  Data traces cause a Tcl command to be executed whenever
data fields are 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.
Note: operations on arrays trigger on the whole key value,
not the individual array element.
.PP
The tree's \fBget\fR, \fBset\fR, and \fBunset\fR operations can 
trigger various traces.  The \fBget\fR operation can cause 
a \fIread\fR  trace to fire.  The \fBset\fR operation causes a \fIwrite\fR 
trace to fire.  And if the data field is written for the first time, you
will also get a \fIcreate\fR trace.
The \fBunset\fR operation triggers \fIunset\fR traces.
.PP
Data traces are invoked by the \fBtrace\fR
operation.  The general form is
.DS
\fItreeName\fR \fBtrace\fR \fIoperation\fR ?\fIarg\fR?...
.DE
Both \fIoperation\fR and its arguments determine the exact behavior of
the command.  The operations available for traces are listed below.
.TP
\fItreeName\fR \fBtrace create\fR \fInode\fR \fIkey\fR \fIops\fR \fIcommand\fR ?-bgerror?
Create a trace on data fields (or tags for tag traces)
given by the pattern in \fIkey\fR.  The \fInode\fR argument
can be a nodeid, or a tag to refer to multiple nodes eg. \fIall\fR.
The return value is an identifier that can
be used with "\fBtrace info\fR" or "\fBtrace delete\fR".
Traces are temporarily disabled while executing \fIcommand\fR within the trace.
.sp
\fICommand\fR is a command prefix, to which
four arguments are appended before invocation:
\fItreeName\fR, \fInodeid\fR, \fIkey\fR and, \fIops\fR.
If an error occurs in \fIcommand\fR (and \fI-bgerror\fR was not used)
the invoking operation will also abort.
.sp
\fIOps\fR indicates which operations are of
interest.  It consists of one or more of the following letters:
.RS
.TP
\fBr\fR
Invoke \fIcommand\fR whenever \fIkey\fR is read.
.TP
\fBw\fR
Invoke \fIcommand\fR whenever \fIkey\fR is written.
.TP
\fBc\fR
Invoke \fIcommand\fR whenever \fIkey\fR is created.
.TP
\fBu\fR 
Invoke \fIcommand\fR whenever \fIkey\fR is unset,
typically with the \fBunset\fR command.
to that.
.TP
\fBe\fR
Invoke \fIcommand\fR whenever \fBexists\fR is used on an non-existant
key.  This can be used to populate node key data on demand.
.TP
\fBt\fR
Invoke \fIcommand\fR whenever tag \fIkey\fR is added to a node.
.TP
\fBm\fR
Invoke \fIcommand\fR when tag \fIkey\fR gets added to more than one node.
This trace can be used to enforce tags that should be on at most one node.
It can avoid later errors with tags used in
\fBget\fR or other commands not accepting non-unique tags.
.TP
\fBd\fR
Invoke \fIcommand\fR whenever tag \fIkey\fR is \fIdeleted\fR from a node
using either \fBtag delete\fR or \fBtag forget\fR.
Node deletion will not trigger this trace.
.sp
.RE
.TP
\fItreeName\fR \fBtrace delete\fR \fItraceId\fR...
Deletes one of more traces.  \fITraceId\fR is
the trace identifier returned by the \fBtrace create\fR operation.
.TP
\fItreeName\fR \fBtrace info\fR \fItraceId\fR 
Returns information about the trace \fItraceId\fR.  \fITraceId\fR
is a trace identifier previously returned by the \fBtrace create\fR operation.
It's the same information specified for the \fBtrace create\fR 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 \fIops\fR) and, the command prefix.
.TP
\fItreeName\fR \fBtrace names\fR
Returns a list of identifers for all the current traces.
.SH NOTIFY OPERATIONS
The purpose of \fBnotify\fR is to get control when structural operations
occur on a tree.  This is used internally by \fBtreeview\fR or example when a
tree object is shared.  A client may create nodes,
sort a tree, move a node, etc.  Notifier
can cause such operations to generate events,
resulting in Tcl commands being executed.
.PP
The general form of \fBnotify\fR is:
.PP
.RS
\fItreeName\fR \fBnotify\fR \fIoperation\fR ?\fIarg\fR?...
.RE
.PP
The available \fIoperation\fR are as follows:
.TP
\fItreeName\fR \fBnotify create\fR ?\fIswitches\fR? \fIcommand\fR ?\fIargs\fR?...  
Creates a notifier for the tree.  A notify identifier in the form
"\fBnotify0\fR", "\fBnotify1\fR", etc.  is returned.
.sp
\fICommand\fR and \fIargs\fR are saved and invoked whenever the tree
structure is changed (controlled by \fIswitches\fR). Two arguments are
appended to \fIcommand\fR and \fIargs\fR before it's invoked: the id
of the node and a string representing the type of event that occured.
If an error is returned by \fIcommand\fR
the invoking operation returns an error (when not using \fI-whenidle\fR).
One or more of the following switches are used to indicate the events
that are of interest:
.RS
.TP 1i
\fB\-bgerror\fR 
Generate a background error if an error occurs.
.TP 1i
\fB\-create\fR 
Invoke \fIcommand\fR whenever a new node is added.
This is called after the creation.  Returning an error will
delete the node.
.TP 1i
\fB\-delete\fR
Invoke \fIcommand\fR whenever a node has been deleted.
This is called before the delete starts to allow aborting it with an error.
Deletes resulting from failed inserts are ignored.
.TP 1i
\fB\-disabletrace\fR 
Disable traces from firing during a notify event.
.TP 1i
\fB\-get\fR 
Invoke \fIcommand\fR whenever a node with no keys is accessed (via \fBget\fR
or \fBwith\fR).
If a node has at least one key, this will not trigger.
The invocation occurs before the read, meaning it can
be used to implement demand loading of data keys into empty nodes
(eg. loading database row data on read).
.TP 1i
\fB\-insert\fR
Invoke \fIcommand\fR when an \fBinsert\fR completes.
This differs from \fB-create\fR in that the call occurs
after the label, tags and data are added (but before
\fB-fixed\fR gets set).
This trace applies to the subcommands \fBcreate\fR, \fBcopy\fR,
\fBrestore\fR, \fBsqlload\fR, and
\fBinsert\fR (both tree and treeview).
It is useful for verifying key-data, tags and labels.
Returning an error will delete the node and cause the
originating command to generate an error.
.TP 1i
\fB\-move\fR
Invoke \fIcommand\fR at the start of a node move.
.TP 1i
\fB\-movepost\fR
Invoke \fIcommand\fR after a node has been moved.
.TP 1i
\fB\-sort\fR
Invoke \fIcommand\fR whenever the tree has been sorted and reordered.
.TP 1i
\fB\-relabel\fR
Invoke \fIcommand\fR at the start of a node relabel.
.TP 1i
\fB\-relabelpost\fR
Invoke \fIcommand\fR after a node has been relabeled.
.TP 1i
\fB\-allevents\fR
Invoke \fIcommand\fR whenever any of the above events occur.
.TP 1i
\fB\-whenidle\fR
When an event occurs don't invoke \fIcommand\fR 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, \fIcommand\fR will still be 
invoked only once.
.RE
.TP
\fItreeName\fR \fBnotify delete\fR \fInotifyId\fR 
Deletes one or more notifiers from the tree.  \fINotifyId\fR is the
notifier identifier returned by the \fBnotify create\fR operation.
.TP
\fItreeName\fR \fBnotify info\fR \fInotifyId\fR
Returns information about the notify event \fInotifyId\fR.  \fINotifyId\fR
is a notify identifier previously returned by the \fBnotify create\fR operation.
It's the same information specified for the \fBnotify create\fR operation.
It consists of the notify id, a sublist of event flags (it's in the same
form as \fIflags\fR) and, the command prefix.
.TP
\fItreeName\fR \fBnotify names\fR
Returns a list of identifers for all the current notifiers.

.SH TABLE EXAMPLE
The following is a simple example.
.sp
.CS
 variable Users {
     tom  { Name "Tom Brown"  Sex M Age 19  Class {4 5} Rate {A 1 B 2}}
     mary { Name "Mary Brown" Sex F Age 16  Class {5}   Rate {A 2}}
     sam  { Name "Sam Spade"  Sex M Age 19  Class {3 4} Rate {B 3}}
 }
 set t [tree create]
 foreach {i d} $Users {
    # Use name in -tags so we don't have to do "0->mary" etc.
    $t insert 0 -tags $i -data $d -label $i
 }
 
 $t update   tom       Sex F   Name "Tomi Brown"
 $t append   sam       Name " Jr"
 $t lappend  sam       Class 5
 $t incr     mary      Age
 $t update   tom       Rate(A) 2
 $t incr     0->mary   Age
 
 # Set a trace.
 proc ::Aupd {t id key op} { tclLog "AA: $t $id $key $op" }
 $t trace create all Age w ::Aupd
 $t incr     mary Age
 
 # Display it.
 pack [treeview .t -tree $t] -fill both -expand y
 eval .t column insert end [$t keys all]
.CE
.SH TREE EXAMPLE
The following is a nested tree example with updates.
.sp
.CS
 variable Info {
   system {
      sol  { OS Linux Version 3.4 }
      bing { OS Win Version 7 }
      gui  { OS Mac Version 8 }
   }
   network {
      intra { Address 192.168.1  Netmask 255.255.255.0 }
      dmz   { Address 192.168.10 Netmask 255.255.255.0 }
      wan   { Address 0.0.0.0 Netmask 0.0.0.0 Class {A 1 B 4}}
   }
   admins {
      sully { Name "Sully Van Damme" Level 3 }
      maverick { Name "Maverick Gump" Level 1 }
   }
 }
  
 set s [tree create]
 foreach {n vals} $Info {
   set ind [$s insert 0 -label $n]
   foreach {i d} $vals {
      $s insert $ind -label $i -data $d
   }
 }
  
 set old [$s get  0->system->bing]
 $s update   0->system->bing   OS Linux Version 3.4
 $s update   0->network->dmz   Address 192.168.11
 $s update   0->network->wan   Class(A) 2
 eval $s set 0->system->bing   $old
 $s insert   0->admins -label linus -data { Name "Linus Torvalds" Level 9 }
 
 
 pack [treeview .s -tree $s -width 600] -fill both -expand y
 eval .s column insert end [$s keys all]
.CE
.SH SQLLOAD EXAMPLE
Here is an example using \fBsqlload\fR on table \fIcust\fR from a
database file, and displaying it in a treeview:
.CS
  set t [tree create]
  $t sqlload mydb.dat "select rowid,* from cust"
  pack [treeview .t -tree $t -width 500] -fill both -expand y
  eval .t column insert end [lsort [$t keys all]]
.CE
Although there is no corresponding \fBsqldump\fR command,
scripting it is easy.  Following
is one approach.
.CS
  proc sqldump {t db table {ids {}}} {
      # Dump nodes from tree t into table in open sqlite database db.
      if {$ids == {}} { set ids [$t children root] }
      set keys [$t keys $ids]
      catch { $db eval "CREATE TABLE $table ( [join $keys ,] )" }
      $t with s $ids {
          set nams {}
          set vals {}
          foreach nam $s(*) {
              lappend vals $s($nam)
              lappend nams $nam
          }
          set vals [join $vals ,]
          set nams [join $nams ,]
          set q [format {INSERT INTO %s (%s) VALUES (%s)} $table $nams $vals]
          $db eval $q
      }
  }
  sqlite3 [set db dbhandle] mydb.dat
  sqldump $t $db cust2
.CE
.SH TREE KEY STRING STORAGE
Key name strings
are stored by default in a global hash table.
However, sometimes this can be undesirable (eg. with threading),
and so the behavior may be changed (at tree create time only).
To enable per-interp storage of keys, set
\fBblt::treeKeysLocal\fR to 1 before tree creation.
To enable per-tree storage of keys, set
\fBblt::treeKeysLocal\fR to 2 before tree creation.
The above is unavailable in safe interps.
.SH 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.
.SH KEYWORDS
tree, treeview, widget