struct::graph1(3tcl) Tcl Data Structures struct::graph1(3tcl)______________________________________________________________________________NAME
struct::graph1 - Create and manipulate directed graph objects (version
1)
SYNOPSIS
package require Tcl 8.2
package require struct::graph ?1.2.1?
graphName option ?arg arg ...?
graphName destroy
graphName arc append arc ?-key key? value
graphName arc delete arc ?arc ...?
graphName arc exists arc
graphName arc get arc ?-key key?
graphName arc getall arc
graphName arc keys arc
graphName arc keyexists arc ?-key key?
graphName arc insert start end ?child?
graphName arc lappend arc ?-key key? value
graphName arc set arc ?-key key? ?value?
graphName arc source arc
graphName arc target arc
graphName arc unset arc ?-key key?
graphName arcs ?-key key? ?-value value? ?-in|-out|-adj|-inner|-embed‐
ding nodelist?
graphName node append node ?-key key? value
graphName node degree ?-in|-out? node
graphName node delete node ?node ...?
graphName node exists node
graphName node get node ?-key key?
graphName node getall node
graphName node keys node
graphName node keyexists node ?-key key?
graphName node insert ?child?
graphName node lappend node ?-key key? value
graphName node opposite node arc
graphName node set node ?-key key? ?value?
graphName node unset node ?-key key?
graphName nodes ?-key key? ?-value value? ?-in|-out|-adj|-inner|-embed‐
ding nodelist?
graphName get ?-key key?
graphName getall
graphName keys
graphName keyexists ?-key key?
graphName set ?-key key? ?value?
graphName swap node1 node2
graphName unset ?-key key?
graphName walk node ?-order order? ?-type type? ?-dir direction? -com‐
mand cmd
_________________________________________________________________DESCRIPTION
The ::struct::graph command creates a new graph object with an associ‐
ated global Tcl command whose name is graphName. This command may be
used to invoke various operations on the graph. It has the following
general form:
graphName option ?arg arg ...?
Option and the args determine the exact behavior of the command.
A directed graph is a structure containing two collections of elements,
called nodes and arcs respectively, together with a relation ("connec‐
tivity") that places a general structure upon the nodes and arcs.
Each arc is connected to two nodes, one of which is called the source
and the other the target. This imposes a direction upon the arc, which
is said to go from the source to the target. It is allowed that source
and target of an arc are the same node. Such an arc is called a loop.
Whenever a node is source or target of an arc both are said to be adja‐
cent. This extends into a relation between nodes, i.e. if two nodes are
connected through at least one arc they are said to be adjacent too.
Each node can be the source and target for any number of arcs. The for‐
mer are called the outgoing arcs of the node, the latter the incoming
arcs of the node. The number of edges in either set is called the in-
resp. the out-degree of the node.
In addition to maintaining the node and arc relationships, this graph
implementation allows any number of keyed values to be associated with
each node and arc.
The following commands are possible for graph objects:
graphName destroy
Destroy the graph, including its storage space and associated
command.
graphName arc append arc ?-key key? value
Appends a value to one of the keyed values associated with an
arc. If no key is specified, the key data is assumed.
graphName arc delete arc ?arc ...?
Remove the specified arcs from the graph.
graphName arc exists arc
Return true if the specified arc exists in the graph.
graphName arc get arc ?-key key?
Return the value associated with the key key for the arc. If no
key is specified, the key data is assumed.
graphName arc getall arc
Returns a serialized list of key/value pairs (suitable for use
with [array set]) for the arc.
graphName arc keys arc
Returns a list of keys for the arc.
graphName arc keyexists arc ?-key key?
Return true if the specified key exists for the arc. If no key
is specified, the key data is assumed.
graphName arc insert start end ?child?
Insert an arc named child into the graph beginning at the node
start and ending at the node end. If the name of the new arc is
not specified the system will generate a unique name of the form
arcx.
graphName arc lappend arc ?-key key? value
Appends a value (as a list) to one of the keyed values associ‐
ated with an arc. If no key is specified, the key data is
assumed.
graphName arc set arc ?-key key? ?value?
Set or get one of the keyed values associated with an arc. If
no key is specified, the key data is assumed. Each arc that is
added to a graph has the empty string assigned to the key data
automatically. An arc may have any number of keyed values asso‐
ciated with it. If value is not specified, this command returns
the current value assigned to the key; if value is specified,
this command assigns that value to the key.
graphName arc source arc
Return the node the given arc begins at.
graphName arc target arc
Return the node the given arc ends at.
graphName arc unset arc ?-key key?
Remove a keyed value from the arc arc. If no key is specified,
the key data is assumed.
graphName arcs ?-key key? ?-value value? ?-in|-out|-adj|-inner|-embed‐
ding nodelist?
Return a list of arcs in the graph. If no restriction is speci‐
fied a list containing all arcs is returned. Restrictions can
limit the list of returned arcs based on the nodes that are con‐
nected by the arc, on the keyed values associated with the arc,
or both. The restrictions that involve connected nodes have a
list of nodes as argument, specified after the name of the
restriction itself.
-in Return a list of all arcs whose target is one of the
nodes in the nodelist.
-out Return a list of all arcs whose source is one of the
nodes in the nodelist.
-adj Return a list of all arcs adjacent to at least one of the
nodes in the nodelist. This is the union of the nodes
returned by -in and -out.
-inner Return a list of all arcs adjacent to two of the nodes in
the nodelist. This is the set of arcs in the subgraph
spawned by the specified nodes.
-embedding
Return a list of all arcs adjacent to exactly one of the
nodes in the nodelist. This is the set of arcs connecting
the subgraph spawned by the specified nodes to the rest
of the graph.
-key key
Limit the list of arcs that are returned to those arcs
that have an associated key key.
-value value
This restriction can only be used in combination with
-key. It limits the list of arcs that are returned to
those arcs whose associated key key has the value value.
The restrictions imposed by either -in, -out, -adj, -inner, or -embed‐
ded are applied first. Specifying more than one of them is illegal. At
last the restrictions set via -key (and -value) are applied. Specify‐
ing more than one -key (and -value) is illegal.
graphName node append node ?-key key? value
Appends a value to one of the keyed values associated with an
node. If no key is specified, the key data is assumed.
graphName node degree ?-in|-out? node
Return the number of arcs adjacent to the specified node. If one
of the restrictions -in or -out is given only the incoming resp.
outgoing arcs are counted.
graphName node delete node ?node ...?
Remove the specified nodes from the graph. All of the nodes'
arcs will be removed as well to prevent unconnected arcs.
graphName node exists node
Return true if the specified node exists in the graph.
graphName node get node ?-key key?
Return the value associated with the key key for the node. If
no key is specified, the key data is assumed.
graphName node getall node
Returns a serialized list of key/value pairs (suitable for use
with [array set]) for the node.
graphName node keys node
Returns a list of keys for the node.
graphName node keyexists node ?-key key?
Return true if the specified key exists for the node. If no key
is specified, the key data is assumed.
graphName node insert ?child?
Insert a node named child into the graph. The nodes has no arcs
connected to it. If the name of the new child is not specified
the system will generate a unique name of the form nodex.
graphName node lappend node ?-key key? value
Appends a value (as a list) to one of the keyed values associ‐
ated with an node. If no key is specified, the key data is
assumed.
graphName node opposite node arc
Return the node at the other end of the specified arc, which has
to be adjacent to the given node.
graphName node set node ?-key key? ?value?
Set or get one of the keyed values associated with a node. If
no key is specified, the key data is assumed. Each node that is
added to a graph has the empty string assigned to the key data
automatically. A node may have any number of keyed values asso‐
ciated with it. If value is not specified, this command returns
the current value assigned to the key; if value is specified,
this command assigns that value to the key.
graphName node unset node ?-key key?
Remove a keyed value from the node node. If no key is speci‐
fied, the key data is assumed.
graphName nodes ?-key key? ?-value value? ?-in|-out|-adj|-inner|-embed‐
ding nodelist?
Return a list of nodes in the graph. Restrictions can limit the
list of returned nodes based on neighboring nodes, or based on
the keyed values associated with the node. The restrictions that
involve neighboring nodes have a list of nodes as argument,
specified after the name of the restriction itself.
The possible restrictions are the same as for method arcs. The
set of nodes to return is computed as the union of all source
and target nodes for all the arcs satisfying the restriction as
defined for arcs.
graphName get ?-key key?
Return the value associated with the key key for the graph. If
no key is specified, the key data is assumed.
graphName getall
Returns a serialized list of key/value pairs (suitable for use
with [array set]) for the whole graph.
graphName keys
Returns a list of keys for the whole graph.
graphName keyexists ?-key key?
Return true if the specified key exists for the whole graph. If
no key is specified, the key data is assumed.
graphName set ?-key key? ?value?
Set or get one of the keyed values associated with a graph. If
no key is specified, the key data is assumed. Each graph has the
empty string assigned to the key data automatically. A graph may
have any number of keyed values associated with it. If value is
not specified, this command returns the current value assigned
to the key; if value is specified, this command assigns that
value to the key.
graphName swap node1 node2
Swap the position of node1 and node2 in the graph.
graphName unset ?-key key?
Remove a keyed value from the graph. If no key is specified, the
key data is assumed.
graphName walk node ?-order order? ?-type type? ?-dir direction? -com‐
mand cmd
Perform a breadth-first or depth-first walk of the graph start‐
ing at the node node going in either the direction of outgoing
or opposite to the incoming arcs.
The type of walk, breadth-first or depth-first, is determined by
the value of type; bfs indicates breadth-first, dfs indicates
depth-first. Depth-first is the default.
The order of the walk, pre-order, post-order or both-order is
determined by the value of order; pre indicates pre-order, post
indicates post-order, both indicates both-order. Pre-order is
the default. Pre-order walking means that a node is visited
before any of its neighbors (as defined by the direction, see
below). Post-order walking means that a parent is visited after
any of its neighbors. Both-order walking means that a node is
visited before and after any of its neighbors. The combination
of a bread-first walk with post- or both-order is illegal.
The direction of the walk is determined by the value of dir;
backward indicates the direction opposite to the incoming arcs,
forward indicates the direction of the outgoing arcs.
As the walk progresses, the command cmd will be evaluated at
each node, with the mode of the call (enter or leave) and values
graphName and the name of the current node appended. For a pre-
order walk, all nodes are entered, for a post-order all nodes
are left. In a both-order walk the first visit of a node enters
it, the second visit leaves it.
BUGS, IDEAS, FEEDBACK
This document, and the package it describes, will undoubtedly contain
bugs and other problems. Please report such in the category struct ::
graph of the Tcllib SF Trackers [http://source‐
forge.net/tracker/?group_id=12883]. Please also report any ideas for
enhancements you may have for either package and/or documentation.
KEYWORDS
cgraph, graph
CATEGORY
Data structures
COPYRIGHT
Copyright (c) 2002 Andreas Kupries <andreas_kupries@users.sourceforge.net>
struct 1.2.1 struct::graph1(3tcl)
