[//000000001]: # (struct::graph\_v1 \- Tcl Data Structures) [//000000002]: # (Generated from file 'graph1\.man' by tcllib/doctools with format 'markdown') [//000000003]: # (Copyright © 2002 Andreas Kupries ) [//000000004]: # (struct::graph\_v1\(n\) 1\.2\.1 tcllib "Tcl Data Structures")
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# NAME struct::graph\_v1 \- Create and manipulate directed graph objects # Table Of Contents - [Table Of Contents](#toc) - [Synopsis](#synopsis) - [Description](#section1) - [Bugs, Ideas, Feedback](#section2) - [Keywords](#keywords) - [Category](#category) - [Copyright](#copyright) # SYNOPSIS package require Tcl 8\.2 package require struct::graph ?1\.2\.1? [__graphName__ *option* ?*arg arg \.\.\.*?](#1) [*graphName* __destroy__](#2) [*graphName* __arc append__ *arc* ?\-key *key*? *value*](#3) [*graphName* __arc delete__ *arc* ?*arc* \.\.\.?](#4) [*graphName* __arc exists__ *arc*](#5) [*graphName* __arc get__ *arc* ?\-key *key*?](#6) [*graphName* __arc getall__ *arc*](#7) [*graphName* __arc keys__ *arc*](#8) [*graphName* __arc keyexists__ *arc* ?\-key *key*?](#9) [*graphName* __arc insert__ *start* *end* ?*child*?](#10) [*graphName* __arc lappend__ *arc* ?\-key *key*? *value*](#11) [*graphName* __arc set__ *arc* ?\-key *key*? ?*value*?](#12) [*graphName* __arc source__ *arc*](#13) [*graphName* __arc target__ *arc*](#14) [*graphName* __arc unset__ *arc* ?\-key *key*?](#15) [*graphName* __arcs__ ?\-key *key*? ?\-value *value*? ?\-in|\-out|\-adj|\-inner|\-embedding *nodelist*?](#16) [*graphName* __node append__ *node* ?\-key *key*? *value*](#17) [*graphName* __node degree__ ?\-in|\-out? *node*](#18) [*graphName* __node delete__ *node* ?*node* \.\.\.?](#19) [*graphName* __node exists__ *node*](#20) [*graphName* __node get__ *node* ?\-key *key*?](#21) [*graphName* __node getall__ *node*](#22) [*graphName* __node keys__ *node*](#23) [*graphName* __node keyexists__ *node* ?\-key *key*?](#24) [*graphName* __node insert__ ?*child*?](#25) [*graphName* __node lappend__ *node* ?\-key *key*? *value*](#26) [*graphName* __node opposite__ *node* *arc*](#27) [*graphName* __node set__ *node* ?\-key *key*? ?*value*?](#28) [*graphName* __node unset__ *node* ?\-key *key*?](#29) [*graphName* __nodes__ ?\-key *key*? ?\-value *value*? ?\-in|\-out|\-adj|\-inner|\-embedding *nodelist*?](#30) [*graphName* __get__ ?\-key *key*?](#31) [*graphName* __getall__](#32) [*graphName* __keys__](#33) [*graphName* __keyexists__ ?\-key *key*?](#34) [*graphName* __set__ ?\-key *key*? ?*value*?](#35) [*graphName* __swap__ *node1* *node2*](#36) [*graphName* __unset__ ?\-key *key*?](#37) [*graphName* __walk__ *node* ?\-order *order*? ?\-type *type*? ?\-dir *direction*? \-command *cmd*](#38) # DESCRIPTION The __::struct::graph__ command creates a new graph object with an associated 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 *arg*s 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 \("connectivity"\) 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 *adjacent*\. 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 former 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 *arc**x*\. - *graphName* __arc lappend__ *arc* ?\-key *key*? *value* Appends a *value* \(as a list\) to one of the keyed values associated 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 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* __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|\-embedding *nodelist*? Return a list of arcs in the graph\. If no restriction is specified a list containing all arcs is returned\. Restrictions can limit the list of returned arcs based on the nodes that are connected 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 __\-embedded__ are applied first\. Specifying more than one of them is illegal\. At last the restrictions set via __\-key__ \(and __\-value__\) are applied\. Specifying 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 *node**x*\. - *graphName* __node lappend__ *node* ?\-key *key*? *value* Appends a *value* \(as a list\) to one of the keyed values associated with an *node*\. If no *key* is specified, the key __data__ is assumed\. - *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 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* __node unset__ *node* ?\-key *key*? Remove a keyed value from the node *node*\. If no key is specified, the key __data__ is assumed\. - *graphName* __nodes__ ?\-key *key*? ?\-value *value*? ?\-in|\-out|\-adj|\-inner|\-embedding *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*? \-command *cmd* Perform a breadth\-first or depth\-first walk of the graph starting 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 __enter__ed, for a post\-order all nodes are left\. In a both\-order walk the first visit of a node __enter__s it, the second visit __leave__s 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 Trackers](http://core\.tcl\.tk/tcllib/reportlist)\. Please also report any ideas for enhancements you may have for either package and/or documentation\. When proposing code changes, please provide *unified diffs*, i\.e the output of __diff \-u__\. Note further that *attachments* are strongly preferred over inlined patches\. Attachments can be made by going to the __Edit__ form of the ticket immediately after its creation, and then using the left\-most button in the secondary navigation bar\. # KEYWORDS [cgraph](\.\./\.\./\.\./\.\./index\.md\#cgraph), [graph](\.\./\.\./\.\./\.\./index\.md\#graph) # CATEGORY Data structures # COPYRIGHT Copyright © 2002 Andreas Kupries