5 Graph Description Language (GDL) - Absint

5.15 GDL’s Grammar
This section presents the grammar of GDL (Graph Description Language) in EBNF (Extended
Bacchus Naur Form).
• Terminals are enclosed in “double quotes” and printed in bold.
• Nonterminals are written in italics
• Finite iterations are specified by (...) ∗
graph : “graph: {” (graph_entry) ∗ “}”
graph_entry : graph_attribute
| graph
| node
| edge
| node_defaults
| edge_defaults
| foldnode_defaults
| foldedge_defaults
| backedge
| nearedge
| lnearedge
| rnearedge
| bentnearedge
| lbentnearedge
| rbentnearedge
| region
graph_attribute : graph_attribute_name “:” attribute_value
graph_attribute_name : any attribute listed in section 5.7
node_defaults : “node.”node_attribute
edge_defaults : “edge.”edge_attribute
foldnode_defaults : “foldnode.”node_attribute
foldedge_defaults : “foldedge.”edge_attribute
node : “node: {” (node_attribute) ∗ “}”
edge : “edge: {” (edge_attribute) ∗ “}”
backedge : “backedge: {” (edge_attribute) ∗ “}”
nearedge : “nearedge: {” (edge_attribute) ∗ “}”
lnearedge : “leftnearedge: {” (edge_attribute) ∗ “}”
rnearedge : “rightnearedge: {” (edge_attribute) ∗ “}”
bentnearedge : “bentnearedge: {” (edge_attribute) ∗ “}”
lbentnearedge : “leftbentnearedge: {” (edge_attribute) ∗ “}”
rbentnearedge : “rightbentnearedge: {” (edge_attribute) ∗ “}”
region : “region: {” (region_attribute) ∗ “}”
node_attribute : node_attribute_name “:” attribute_value
edge_attribute : edge_attribute_name “:” attribute_value
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