1gv(3lua)                                                              gv(3lua)
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NAME

6       gv_lua - graph manipulation in lua
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SYNOPSIS

10       #!/usr/bin/lua
11       require('gv')
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USAGE

INTRODUCTION

16       gv_lua  is  a dynamically loaded extension for lua that provides access
17       to the graph facilities of graphviz.
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COMMANDS

21       New graphs
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23       New empty graph
24              graph_handle gv.graph (name);
25              graph_handle gv.digraph (name);
26              graph_handle gv.strictgraph (name);
27              graph_handle gv.strictdigraph (name);
28
29       New graph from a dot-syntax string or file
30              graph_handle gv.readstring (string);
31              graph_handle gv.read (string filename);
32              graph_handle gv.read (channel);
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34       Add new subgraph to existing graph
35              graph_handle gv.graph (graph_handle, name);
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37       New nodes
38
39       Add new node to existing graph
40              node_handle gv.node (graph_handle, name);
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42       New edges
43
44       Add new edge between existing nodes
45              edge_handle gv.edge (tail_node_handle, head_node_handle);
46
47       Add a new edge between an existing tail node, and  a  named  head  node
48       which will be induced in the graph if it doesn't already exist
49              edge_handle gv.edge (tail_node_handle, head_name);
50
51       Add  a  new  edge  between an existing head node, and a named tail node
52       which will be induced in the graph if it doesn't already exist
53              edge_handle gv.edge (tail_name, head_node_handle);
54
55       Add a new edge between named tail  and head nodes which will be induced
56       in the graph if they don't already exist
57              edge_handle gv.edge (graph_handle, tail_name, head_name);
58
59       Setting attribute values
60
61       Set value of named attribute of graph/node/edge - creating attribute if
62       necessary
63              string gv.setv (graph_handle, attr_name, attr_value);
64              string gv.setv (node_handle, attr_name, attr_value);
65              string gv.setv (edge_handle, attr_name, attr_value);
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67       Set value of existing attribute  of  graph/node/edge  (using  attribute
68       handle)
69              string gv.setv (graph_handle, attr_handle, attr_value);
70              string gv.setv (node_handle, attr_handle, attr_value);
71              string gv.setv (edge_handle, attr_handle, attr_value);
72
73       Getting attribute values
74
75       Get value of named attribute of graph/node/edge
76              string gv.getv (graph_handle, attr_name);
77              string gv.getv (node_handle, attr_name);
78              string gv.getv (edge_handle, attr_name);
79
80       Get value of attribute of graph/node/edge (using attribute handle)
81              string gv.getv (graph_handle, attr_handle);
82              string gv.getv (node_handle, attr_handle);
83              string gv.getv (edge_handle, attr_handle);
84
85       Obtain names from handles
86              string gv.nameof (graph_handle);
87              string gv.nameof (node_handle);
88              string gv.nameof (attr_handle);
89
90       Find handles from names
91              graph_handle gv.findsubg (graph_handle, name);
92              node_handle gv.findnode (graph_handle, name);
93              edge_handle gv.findedge (tail_node_handle, head_node_handle);
94              attribute_handle gv.findattr (graph_handle, name);
95              attribute_handle gv.findattr (node_handle, name);
96              attribute_handle gv.findattr (edge_handle, name);
97
98       Misc graph navigators returning handles
99              node_handle gv.headof (edge_handle);
100              node_handle gv.tailof (edge_handle);
101              graph_handle gv.graphof (graph_handle);
102              graph_handle gv.graphof (edge_handle);
103              graph_handle gv.graphof (node_handle);
104              graph_handle gv.rootof (graph_handle);
105
106       Obtain handles of proto node/edge for setting default attribute values
107              node_handle gv.protonode (graph_handle);
108              edge_handle gv.protoedge (graph_handle);
109
110       Iterators
111
112       Iteration termination tests
113              bool gv.ok (graph_handle);
114              bool gv.ok (node_handle);
115              bool gv.ok (edge_handle);
116              bool gv.ok (attr_handle);
117
118       Iterate over subgraphs of a graph
119              graph_handle gv.firstsubg (graph_handle);
120              graph_handle gv.nextsubg (graph_handle, subgraph_handle);
121
122       Iterate over supergraphs of a graph (obscure and rarely useful)
123              graph_handle gv.firstsupg (graph_handle);
124              graph_handle gv.nextsupg (graph_handle, subgraph_handle);
125
126       Iterate over edges of a graph
127              edge_handle gv.firstedge (graph_handle);
128              edge_handle gv.nextedge (graph_handle, edge_handle);
129
130       Iterate over outedges of a graph
131              edge_handle gv.firstout (graph_handle);
132              edge_handle gv.nextout (graph_handle, edge_handle);
133
134       Iterate over edges of a node
135              edge_handle gv.firstedge (node_handle);
136              edge_handle gv.nextedge (node_handle, edge_handle);
137
138       Iterate over out-edges of a node
139              edge_handle gv.firstout (node_handle);
140              edge_handle gv.nextout (node_handle, edge_handle);
141
142       Iterate over head nodes reachable from out-edges of a node
143              node_handle gv.firsthead (node_handle);
144              node_handle gv.nexthead (node_handle, head_node_handle);
145
146       Iterate over in-edges of a graph
147              edge_handle gv.firstin (graph_handle);
148              edge_handle gv.nextin (node_handle, edge_handle);
149
150       Iterate over in-edges of a node
151              edge_handle gv.firstin (node_handle);
152              edge_handle gv.nextin (graph_handle, edge_handle);
153
154       Iterate over tail nodes reachable from in-edges of a node
155              node_handle gv.firsttail (node_handle);
156              node_handle gv.nexttail (node_handle, tail_node_handle);
157
158       Iterate over nodes of a graph
159              node_handle gv.firstnode (graph_handle);
160              node_handle gv.nextnode (graph_handle, node_handle);
161
162       Iterate over nodes of an edge
163              node_handle gv.firstnode (edge_handle);
164              node_handle gv.nextnode (edge_handle, node_handle);
165
166       Iterate over attributes of a graph
167              attribute_handle gv.firstattr (graph_handle);
168              attribute_handle gv.nextattr (graph_handle, attr_handle);
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170       Iterate over attributes of an edge
171              attribute_handle gv.firstattr (edge_handle);
172              attribute_handle gv.nextattr (edge_handle, attr_handle);
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174       Iterate over attributes of a node
175              attribute_handle gv.firstattr (node_handle);
176              attribute_handle gv.nextattr (node_handle, attr_handle);
177
178       Remove graph objects
179              bool gv.rm (graph_handle);
180              bool gv.rm (node_handle);
181              bool gv.rm (edge_handle);
182
183       Layout
184
185       Annotate  a  graph  with  layout attributes and values using a specific
186       layout engine
187              bool gv.layout (graph_handle, string engine);
188
189       Render
190
191       Render a layout into attributes of the graph
192              bool gv.render (graph_handle);
193
194       Render a layout to stdout
195              bool gv.render (graph_handle, string format);
196
197       Render to an open file
198              bool gv.render (graph_handle, string format, channel fout);
199
200       Render a layout to an unopened file by name
201              bool gv.render (graph_handle, string format, string filename);
202
203       Render to a string result
204              string gv.renderresult (graph_handle ing, string format);
205              gv.renderresult (graph_handle, string format, string outdata);
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207       Render to an open channel
208              bool gv.renderchannel (graph_handle, string format, string chan‐
209              nelname);
210
211       Render a layout to a malloc'ed string, to be free'd by the caller
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213       (deprecated - too easy to leak memory)
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215       (still needed for "eval [gv::renderdata $G tk]" )
216              string gv.renderdata (graph_handle, string format);
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218       Writing graph back to file
219              bool gv.write (graph_handle, string filename);
220              bool gv.write (graph_handle, channel);
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222       Graph transformation tools
223              bool gv.tred (graph_handle);
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KEYWORDS

227       graph, dot, neato, fdp, circo, twopi, lua.
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232                               02 September 2020                      gv(3lua)
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