graph/encoding/dot: (un)quote attributes if needed during (un)marshal

graph/encoding/dot/decode.go

@@ -6,6 +6,8 @@ package dot
 
 import (
 	"fmt"
+	"strconv"
+	"strings"
 
 	"gonum.org/v1/gonum/graph"
 	"gonum.org/v1/gonum/graph/encoding"
@@ -41,6 +43,10 @@ type PortSetter interface {
 // Unmarshal parses the Graphviz DOT-encoded data and stores the result in dst.
 // If the number of graphs encoded in data is not one, an error is returned and
 // dst will hold the first graph in data.
+//
+// Attributes and IDs are quoted if needed during marshalling, to conform with
+// valid DOT syntax. Quoted IDs and attributes are unquoted during unmarshaling,
+// so the data is kept in raw form.
 func Unmarshal(data []byte, dst encoding.Builder) error {
 	file, err := dot.ParseBytes(data)
 	if err != nil {
@@ -57,6 +63,10 @@ func Unmarshal(data []byte, dst encoding.Builder) error {
 // stores the result in dst.
 // If the number of graphs encoded in data is not one, an error is returned and
 // dst will hold the first graph in data.
+//
+// Attributes and IDs are quoted if needed during marshalling, to conform with
+// valid DOT syntax. Quoted IDs and attributes are unquoted during unmarshaling,
+// so the data is kept in raw form.
 func UnmarshalMulti(data []byte, dst encoding.MultiBuilder) error {
 	file, err := dot.ParseBytes(data)
 	if err != nil {
@@ -88,7 +98,7 @@ func copyGraph(dst encoding.Builder, src *ast.Graph) (err error) {
 		},
 	}
 	if dst, ok := dst.(DOTIDSetter); ok {
-		dst.SetDOTID(src.ID)
+		dst.SetDOTID(unquoteID(src.ID))
 	}
 	if a, ok := dst.(AttributeSetters); ok {
 		gen.graphAttr, gen.nodeAttr, gen.edgeAttr = a.DOTAttributeSetters()
@@ -118,7 +128,7 @@ func copyMultigraph(dst encoding.MultiBuilder, src *ast.Graph) (err error) {
 		},
 	}
 	if dst, ok := dst.(DOTIDSetter); ok {
-		dst.SetDOTID(src.ID)
+		dst.SetDOTID(unquoteID(src.ID))
 	}
 	if a, ok := dst.(AttributeSetters); ok {
 		gen.graphAttr, gen.nodeAttr, gen.edgeAttr = a.DOTAttributeSetters()
@@ -154,7 +164,7 @@ func (gen *generator) node(dst graph.NodeAdder, id string) graph.Node {
 	}
 	n := dst.NewNode()
 	if n, ok := n.(DOTIDSetter); ok {
-		n.SetDOTID(id)
+		n.SetDOTID(unquoteID(id))
 	}
 	dst.AddNode(n)
 	gen.ids[id] = n
@@ -180,8 +190,8 @@ func (gen *simpleGraph) addStmt(dst encoding.Builder, stmt ast.Stmt) {
 		}
 		for _, attr := range stmt.Attrs {
 			a := encoding.Attribute{
-				Key:   attr.Key,
+				Key:   unquoteID(attr.Key),
-				Value: attr.Val,
+				Value: unquoteID(attr.Val),
 			}
 			if err := n.SetAttribute(a); err != nil {
 				panic(fmt.Errorf("unable to unmarshal node DOT attribute (%s=%s): %v", a.Key, a.Value, err))
@@ -216,8 +226,8 @@ func (gen *simpleGraph) addStmt(dst encoding.Builder, stmt ast.Stmt) {
 		}
 		for _, attr := range stmt.Attrs {
 			a := encoding.Attribute{
-				Key:   attr.Key,
+				Key:   unquoteID(attr.Key),
-				Value: attr.Val,
+				Value: unquoteID(attr.Val),
 			}
 			if err := n.SetAttribute(a); err != nil {
 				panic(fmt.Errorf("unable to unmarshal global %s DOT attribute (%s=%s): %v", dst, a.Key, a.Value, err))
@@ -240,7 +250,7 @@ func applyPortsToEdge(from ast.Vertex, to *ast.Edge, edge graph.Edge) {
 	if ps, isPortSetter := edge.(PortSetter); isPortSetter {
 		if n, vertexIsNode := from.(*ast.Node); vertexIsNode {
 			if n.Port != nil {
-				err := ps.SetFromPort(n.Port.ID, n.Port.CompassPoint.String())
+				err := ps.SetFromPort(unquoteID(n.Port.ID), n.Port.CompassPoint.String())
 				if err != nil {
 					panic(fmt.Errorf("unable to unmarshal edge port (:%s:%s)", n.Port.ID, n.Port.CompassPoint.String()))
 				}
@@ -249,7 +259,7 @@ func applyPortsToEdge(from ast.Vertex, to *ast.Edge, edge graph.Edge) {
 
 		if n, vertexIsNode := to.Vertex.(*ast.Node); vertexIsNode {
 			if n.Port != nil {
-				err := ps.SetToPort(n.Port.ID, n.Port.CompassPoint.String())
+				err := ps.SetToPort(unquoteID(n.Port.ID), n.Port.CompassPoint.String())
 				if err != nil {
 					panic(fmt.Errorf("unable to unmarshal edge DOT port (:%s:%s)", n.Port.ID, n.Port.CompassPoint.String()))
 				}
@@ -372,8 +382,8 @@ func (gen *multiGraph) addStmt(dst encoding.MultiBuilder, stmt ast.Stmt) {
 		}
 		for _, attr := range stmt.Attrs {
 			a := encoding.Attribute{
-				Key:   attr.Key,
+				Key:   unquoteID(attr.Key),
-				Value: attr.Val,
+				Value: unquoteID(attr.Val),
 			}
 			if err := n.SetAttribute(a); err != nil {
 				panic(fmt.Errorf("unable to unmarshal node DOT attribute (%s=%s): %v", a.Key, a.Value, err))
@@ -408,8 +418,8 @@ func (gen *multiGraph) addStmt(dst encoding.MultiBuilder, stmt ast.Stmt) {
 		}
 		for _, attr := range stmt.Attrs {
 			a := encoding.Attribute{
-				Key:   attr.Key,
+				Key:   unquoteID(attr.Key),
-				Value: attr.Val,
+				Value: unquoteID(attr.Val),
 			}
 			if err := n.SetAttribute(a); err != nil {
 				panic(fmt.Errorf("unable to unmarshal global %s DOT attribute (%s=%s): %v", dst, a.Key, a.Value, err))
@@ -485,11 +495,30 @@ func addEdgeAttrs(edge graph.Edge, attrs []*ast.Attr) {
 	}
 	for _, attr := range attrs {
 		a := encoding.Attribute{
-			Key:   attr.Key,
+			Key:   unquoteID(attr.Key),
-			Value: attr.Val,
+			Value: unquoteID(attr.Val),
 		}
 		if err := e.SetAttribute(a); err != nil {
 			panic(fmt.Errorf("unable to unmarshal edge DOT attribute (%s=%s): %v", a.Key, a.Value, err))
 		}
 	}
 }
+
+// unquoteID unquotes the given string if needed in the context of an ID. If s
+// is not already quoted the original string is returned.
+func unquoteID(s string) string {
+	// To make round-trips idempotent, don't unquote quoted HTML-like strings
+	//
+	//    /^"<.*>"$/
+	if len(s) >= 4 && strings.HasPrefix(s, `"<`) && strings.HasSuffix(s, `>"`) {
+		return s
+	}
+	// Unquote quoted string if possible.
+	if t, err := strconv.Unquote(s); err == nil {
+		return t
+	}
+	// On error, either s is not quoted or s is quoted but contains invalid
+	// characters, in both cases we return the original string rather than
+	// panicking.
+	return s
+}

graph/encoding/dot/decode_test.go

@@ -43,6 +43,14 @@ func TestRoundTrip(t *testing.T) {
 			want:     undirectedWithPorts,
 			directed: false,
 		},
+		{
+			want:     directedAttrs,
+			directed: true,
+		},
+		{
+			want:     undirectedAttrs,
+			directed: false,
+		},
 	}
 	for i, g := range golden {
 		var dst encoding.Builder
@@ -165,6 +173,46 @@ const undirectedWithPorts = `strict graph {
 	E:_ -- F:c;
 }`
 
+const directedAttrs = `strict digraph {
+	node [
+		shape=circle
+		style=filled
+		label="NODE"
+	];
+	edge [
+		penwidth=5
+		color=gray
+		label=3.14
+	];
+
+	// Node definitions.
+	A [label=<br>];
+	B [label=-14];
+
+	// Edge definitions.
+	A -> B [label="hello world"];
+}`
+
+const undirectedAttrs = `strict graph {
+	node [
+		shape=circle
+		style=filled
+		label="NODE"
+	];
+	edge [
+		penwidth=5
+		color=gray
+		label=3.14
+	];
+
+	// Node definitions.
+	A [label=<br>];
+	B [label=-14];
+
+	// Edge definitions.
+	A -- B [label="hello world"];
+}`
+
 func TestChainedEdgeAttributes(t *testing.T) {
 	golden := []struct {
 		in, want string

graph/encoding/dot/encode.go

@@ -8,7 +8,9 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
+	"regexp"
 	"sort"
+	"strconv"
 	"strings"
 
 	"gonum.org/v1/gonum/graph"
@@ -82,15 +84,18 @@ type MultiSubgrapher interface {
 	Subgraph() graph.Multigraph
 }
 
-// Marshal returns the DOT encoding for the graph g, applying the prefix
+// Marshal returns the DOT encoding for the graph g, applying the prefix and
-// and indent to the encoding. Name is used to specify the graph name. If
+// indent to the encoding. Name is used to specify the graph name. If name is
-// name is empty and g implements Graph, the returned string from DOTID
+// empty and g implements Graph, the returned string from DOTID will be used.
-// will be used.
 //
 // Graph serialization will work for a graph.Graph without modification,
 // however, advanced GraphViz DOT features provided by Marshal depend on
 // implementation of the Node, Attributer, Porter, Attributers, Structurer,
 // Subgrapher and Graph interfaces.
+//
+// Attributes and IDs are quoted if needed during marshalling, to conform with
+// valid DOT syntax. Quoted IDs and attributes are unquoted during unmarshaling,
+// so the data is kept in raw form.
 func Marshal(g graph.Graph, name, prefix, indent string) ([]byte, error) {
 	var p simpleGraphPrinter
 	p.indent = indent
@@ -105,14 +110,17 @@ func Marshal(g graph.Graph, name, prefix, indent string) ([]byte, error) {
 
 // MarshalMulti returns the DOT encoding for the multigraph g, applying the
 // prefix and indent to the encoding. Name is used to specify the graph name. If
-// name is empty and g implements Graph, the returned string from DOTID
+// name is empty and g implements Graph, the returned string from DOTID will be
-// will be used. If strict is true the output bytes will be prefixed with
+// used.
-// the DOT "strict" keyword.
 //
 // Graph serialization will work for a graph.Multigraph without modification,
 // however, advanced GraphViz DOT features provided by Marshal depend on
 // implementation of the Node, Attributer, Porter, Attributers, Structurer,
 // MultiSubgrapher and Multigraph interfaces.
+//
+// Attributes and IDs are quoted if needed during marshalling, to conform with
+// valid DOT syntax. Quoted IDs and attributes are unquoted during unmarshaling,
+// so the data is kept in raw form.
 func MarshalMulti(g graph.Multigraph, name, prefix, indent string) ([]byte, error) {
 	var p multiGraphPrinter
 	p.indent = indent
@@ -308,7 +316,7 @@ func (p *printer) printFrontMatter(name string, needsIndent, isSubgraph, isDirec
 
 	if name != "" {
 		p.buf.WriteByte(' ')
-		p.buf.WriteString(name)
+		p.buf.WriteString(quoteID(name))
 	}
 
 	p.openBlock(" {")
@@ -316,13 +324,13 @@ func (p *printer) printFrontMatter(name string, needsIndent, isSubgraph, isDirec
 }
 
 func (p *printer) writeNode(n graph.Node) {
-	p.buf.WriteString(nodeID(n))
+	p.buf.WriteString(quoteID(nodeID(n)))
 }
 
 func (p *printer) writePorts(port, cp string) {
 	if port != "" {
 		p.buf.WriteByte(':')
-		p.buf.WriteString(port)
+		p.buf.WriteString(quoteID(port))
 	}
 	if cp != "" {
 		p.buf.WriteByte(':')
@@ -354,17 +362,17 @@ func (p *printer) writeAttributeList(a encoding.Attributer) {
 	case 0:
 	case 1:
 		p.buf.WriteString(" [")
-		p.buf.WriteString(attributes[0].Key)
+		p.buf.WriteString(quoteID(attributes[0].Key))
 		p.buf.WriteByte('=')
-		p.buf.WriteString(attributes[0].Value)
+		p.buf.WriteString(quoteID(attributes[0].Value))
 		p.buf.WriteString("]")
 	default:
 		p.openBlock(" [")
 		for _, att := range attributes {
 			p.newline()
-			p.buf.WriteString(att.Key)
+			p.buf.WriteString(quoteID(att.Key))
 			p.buf.WriteByte('=')
-			p.buf.WriteString(att.Value)
+			p.buf.WriteString(quoteID(att.Value))
 		}
 		p.closeBlock("]")
 	}
@@ -388,9 +396,9 @@ func (p *printer) writeAttributeComplex(ca Attributers) {
 		p.openBlock(" [")
 		for _, att := range attributes {
 			p.newline()
-			p.buf.WriteString(att.Key)
+			p.buf.WriteString(quoteID(att.Key))
 			p.buf.WriteByte('=')
-			p.buf.WriteString(att.Value)
+			p.buf.WriteString(quoteID(att.Value))
 		}
 		p.closeBlock("]")
 		haveWrittenBlock = true
@@ -580,3 +588,74 @@ func (p *multiGraphPrinter) print(g graph.Multigraph, name string, needsIndent,
 
 	return nil
 }
+
+// quoteID quotes the given string if needed in the context of an ID. If s is
+// already quoted, or if s does not contain any spaces or special characters
+// that need escaping, the original string is returned.
+func quoteID(s string) string {
+	// To use a keyword as an ID, it must be quoted.
+	if isKeyword(s) {
+		return strconv.Quote(s)
+	}
+	// Quote if s is not an ID. This includes strings containing spaces, except
+	// if those spaces are used within HTML string IDs (e.g. <foo >).
+	if !isID(s) {
+		return strconv.Quote(s)
+	}
+	return s
+}
+
+// isKeyword reports whether the given string is a keyword in the DOT language.
+func isKeyword(s string) bool {
+	// ref: https://www.graphviz.org/doc/info/lang.html
+	keywords := []string{"node", "edge", "graph", "digraph", "subgraph", "strict"}
+	for _, keyword := range keywords {
+		if strings.EqualFold(s, keyword) {
+			return true
+		}
+	}
+	return false
+}
+
+// FIXME: see if we rewrite this in another way to remove our regexp dependency.
+
+// Regular expression to match identifier and numeral IDs.
+var (
+	reIdent   = regexp.MustCompile(`^[a-zA-Z\200-\377_][0-9a-zA-Z\200-\377_]*$`)
+	reNumeral = regexp.MustCompile(`^[-]?(\.[0-9]+|[0-9]+(\.[0-9]*)?)$`)
+)
+
+// isID reports whether the given string is an ID.
+//
+// An ID is one of the following:
+//
+// 1. Any string of alphabetic ([a-zA-Z\200-\377]) characters, underscores ('_')
+//    or digits ([0-9]), not beginning with a digit;
+// 2. a numeral [-]?(.[0-9]+ | [0-9]+(.[0-9]*)? );
+// 3. any double-quoted string ("...") possibly containing escaped quotes (\");
+// 4. an HTML string (<...>).
+func isID(s string) bool {
+	// 1. an identifier.
+	if reIdent.MatchString(s) {
+		return true
+	}
+	// 2. a numeral.
+	if reNumeral.MatchString(s) {
+		return true
+	}
+	// 3. double-quote string ID.
+	if len(s) >= 2 && strings.HasPrefix(s, `"`) && strings.HasSuffix(s, `"`) {
+		// Check that escape sequences within the double-quotes are valid.
+		if _, err := strconv.Unquote(s); err == nil {
+			return true
+		}
+	}
+	// 4. HTML ID.
+	return isHTMLID(s)
+}
+
+// isHTMLID reports whether the given string an HTML ID.
+func isHTMLID(s string) bool {
+	// HTML IDs have the format /^<.*>$/
+	return len(s) >= 2 && strings.HasPrefix(s, "<") && strings.HasSuffix(s, ">")
+}

graph/encoding/dot/encode_test.go

@@ -950,6 +950,64 @@ var encodeTests = []struct {
 	3 -- 4 [color=red];
 }`,
 	},
+	{
+		g: undirectedEdgeAttrGraphFrom(powerMethodGraph, map[edge][]encoding.Attribute{
+			// label attribute not quoted and containing spaces.
+			{from: 0, to: 2}: {{Key: "label", Value: `hello world`}, {Key: "style", Value: "dashed"}},
+			{from: 2, to: 4}: {},
+			{from: 3, to: 4}: {{Key: "label", Value: `foo bar`}},
+		}),
+
+		want: `strict graph {
+	// Node definitions.
+	0;
+	1;
+	2;
+	3;
+	4;
+
+	// Edge definitions.
+	0 -- 1;
+	0 -- 2 [
+		label="hello world"
+		style=dashed
+	];
+	0 -- 4;
+	1 -- 3;
+	2 -- 3;
+	2 -- 4;
+	3 -- 4 [label="foo bar"];
+}`,
+	},
+	{
+		g: undirectedEdgeAttrGraphFrom(powerMethodGraph, map[edge][]encoding.Attribute{
+			// keywords must be quoted if used as attributes.
+			{from: 0, to: 2}: {{Key: "label", Value: `NODE`}, {Key: "style", Value: "dashed"}},
+			{from: 2, to: 4}: {},
+			{from: 3, to: 4}: {{Key: "label", Value: `subgraph`}},
+		}),
+
+		want: `strict graph {
+	// Node definitions.
+	0;
+	1;
+	2;
+	3;
+	4;
+
+	// Edge definitions.
+	0 -- 1;
+	0 -- 2 [
+		label="NODE"
+		style=dashed
+	];
+	0 -- 4;
+	1 -- 3;
+	2 -- 3;
+	2 -- 4;
+	3 -- 4 [label="subgraph"];
+}`,
+	},
 
 	// Handling nodes with ports.
 	{

graph/encoding/graphql/decode_test.go

@@ -34,33 +34,33 @@ var decodeTests = []struct {
 		},
 		wantDOT: `strict digraph {
   // Node definitions.
-  0x8a10d5a2611fd03f [name="Richard Marquand"];
+  "0x8a10d5a2611fd03f" [name="Richard Marquand"];
-  0xa3cff1a4c3ef3bb6 [
+  "0xa3cff1a4c3ef3bb6" [
     name="Star Wars: Episode V - The Empire Strikes Back"
-    release_date=1980-05-21T00:00:00Z
+    release_date="1980-05-21T00:00:00Z"
     revenue=534000000
     running_time=124
   ];
-  0xb39aa14d66aedad5 [
+  "0xb39aa14d66aedad5" [
     name="Star Wars: Episode VI - Return of the Jedi"
-    release_date=1983-05-25T00:00:00Z
+    release_date="1983-05-25T00:00:00Z"
     revenue=572000000
     running_time=131
   ];
-  0x0312de17a7ee89f9 [name="Luke Skywalker"];
+  "0x0312de17a7ee89f9" [name="Luke Skywalker"];
-  0x3da8d1dcab1bb381 [name="Han Solo"];
+  "0x3da8d1dcab1bb381" [name="Han Solo"];
-  0x4a7d0b5fe91e78a4 [name="Irvin Kernshner"];
+  "0x4a7d0b5fe91e78a4" [name="Irvin Kernshner"];
-  0x718337b9dcbaa7d9 [name="Princess Leia"];
+  "0x718337b9dcbaa7d9" [name="Princess Leia"];
 
   // Edge definitions.
-  0xa3cff1a4c3ef3bb6 -> 0x0312de17a7ee89f9 [label=starring];
+  "0xa3cff1a4c3ef3bb6" -> "0x0312de17a7ee89f9" [label=starring];
-  0xa3cff1a4c3ef3bb6 -> 0x3da8d1dcab1bb381 [label=starring];
+  "0xa3cff1a4c3ef3bb6" -> "0x3da8d1dcab1bb381" [label=starring];
-  0xa3cff1a4c3ef3bb6 -> 0x4a7d0b5fe91e78a4 [label=director];
+  "0xa3cff1a4c3ef3bb6" -> "0x4a7d0b5fe91e78a4" [label=director];
-  0xa3cff1a4c3ef3bb6 -> 0x718337b9dcbaa7d9 [label=starring];
+  "0xa3cff1a4c3ef3bb6" -> "0x718337b9dcbaa7d9" [label=starring];
-  0xb39aa14d66aedad5 -> 0x8a10d5a2611fd03f [label=director];
+  "0xb39aa14d66aedad5" -> "0x8a10d5a2611fd03f" [label=director];
-  0xb39aa14d66aedad5 -> 0x0312de17a7ee89f9 [label=starring];
+  "0xb39aa14d66aedad5" -> "0x0312de17a7ee89f9" [label=starring];
-  0xb39aa14d66aedad5 -> 0x3da8d1dcab1bb381 [label=starring];
+  "0xb39aa14d66aedad5" -> "0x3da8d1dcab1bb381" [label=starring];
-  0xb39aa14d66aedad5 -> 0x718337b9dcbaa7d9 [label=starring];
+  "0xb39aa14d66aedad5" -> "0x718337b9dcbaa7d9" [label=starring];
 }`,
 	},
 	{
@@ -72,52 +72,52 @@ var decodeTests = []struct {
 		},
 		wantDOT: `strict digraph {
   // Node definitions.
-  0x892a6da7ee1fbdec [
+  "0x892a6da7ee1fbdec" [
     age=55
     name=Sarah
   ];
-  0x99b74c1b5ab100ec [
+  "0x99b74c1b5ab100ec" [
     age=35
     name=Artyom
   ];
-  0xb9e12a67e34d6acc [
+  "0xb9e12a67e34d6acc" [
     age=19
     name=Catalina
   ];
-  0xbf104824c777525d [name=Perro];
+  "0xbf104824c777525d" [name=Perro];
-  0xf590a923ea1fccaa [name=Goldie];
+  "0xf590a923ea1fccaa" [name=Goldie];
-  0xf92d7dbe272d680b [name="Hyung Sin"];
+  "0xf92d7dbe272d680b" [name="Hyung Sin"];
-  0x0fd90205a458151f [
+  "0x0fd90205a458151f" [
     age=39
     name=Michael
   ];
-  0x37734fcf0a6fcc69 [name="Rammy the sheep"];
+  "0x37734fcf0a6fcc69" [name="Rammy the sheep"];
-  0x52a80955d40ec819 [
+  "0x52a80955d40ec819" [
     age=35
     name=Amit
   ];
-  0x5e9ad1cd9466228c [
+  "0x5e9ad1cd9466228c" [
     age=24
     name="Sang Hyun"
   ];
 
   // Edge definitions.
-  0xb9e12a67e34d6acc -> 0xbf104824c777525d [label=owns_pet];
+  "0xb9e12a67e34d6acc" -> "0xbf104824c777525d" [label=owns_pet];
-  0xb9e12a67e34d6acc -> 0x5e9ad1cd9466228c [label=friend];
+  "0xb9e12a67e34d6acc" -> "0x5e9ad1cd9466228c" [label=friend];
-  0xf92d7dbe272d680b -> 0x5e9ad1cd9466228c [label=friend];
+  "0xf92d7dbe272d680b" -> "0x5e9ad1cd9466228c" [label=friend];
-  0x0fd90205a458151f -> 0x892a6da7ee1fbdec [label=friend];
+  "0x0fd90205a458151f" -> "0x892a6da7ee1fbdec" [label=friend];
-  0x0fd90205a458151f -> 0x99b74c1b5ab100ec [label=friend];
+  "0x0fd90205a458151f" -> "0x99b74c1b5ab100ec" [label=friend];
-  0x0fd90205a458151f -> 0xb9e12a67e34d6acc [label=friend];
+  "0x0fd90205a458151f" -> "0xb9e12a67e34d6acc" [label=friend];
-  0x0fd90205a458151f -> 0x37734fcf0a6fcc69 [label=owns_pet];
+  "0x0fd90205a458151f" -> "0x37734fcf0a6fcc69" [label=owns_pet];
-  0x0fd90205a458151f -> 0x52a80955d40ec819 [label=friend];
+  "0x0fd90205a458151f" -> "0x52a80955d40ec819" [label=friend];
-  0x0fd90205a458151f -> 0x5e9ad1cd9466228c [label=friend];
+  "0x0fd90205a458151f" -> "0x5e9ad1cd9466228c" [label=friend];
-  0x52a80955d40ec819 -> 0x99b74c1b5ab100ec [label=friend];
+  "0x52a80955d40ec819" -> "0x99b74c1b5ab100ec" [label=friend];
-  0x52a80955d40ec819 -> 0x0fd90205a458151f [label=friend];
+  "0x52a80955d40ec819" -> "0x0fd90205a458151f" [label=friend];
-  0x52a80955d40ec819 -> 0x5e9ad1cd9466228c [label=friend];
+  "0x52a80955d40ec819" -> "0x5e9ad1cd9466228c" [label=friend];
-  0x5e9ad1cd9466228c -> 0xb9e12a67e34d6acc [label=friend];
+  "0x5e9ad1cd9466228c" -> "0xb9e12a67e34d6acc" [label=friend];
-  0x5e9ad1cd9466228c -> 0xf590a923ea1fccaa [label=owns_pet];
+  "0x5e9ad1cd9466228c" -> "0xf590a923ea1fccaa" [label=owns_pet];
-  0x5e9ad1cd9466228c -> 0xf92d7dbe272d680b [label=friend];
+  "0x5e9ad1cd9466228c" -> "0xf92d7dbe272d680b" [label=friend];
-  0x5e9ad1cd9466228c -> 0x52a80955d40ec819 [label=friend];
+  "0x5e9ad1cd9466228c" -> "0x52a80955d40ec819" [label=friend];
 }`,
 	},
 	{