simple dot graph gen

go.mod

@@ -3,6 +3,7 @@ module github.com/ferranbt/fastssz
 go 1.18
 
 require (
+	github.com/emicklei/dot v1.6.2
 	github.com/golang/snappy v0.0.3
 	github.com/minio/sha256-simd v1.0.0
 	github.com/mitchellh/mapstructure v1.3.2

go.sum

@@ -1,6 +1,8 @@
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/emicklei/dot v1.6.2 h1:08GN+DD79cy/tzN6uLCT84+2Wk9u+wvqP+Hkx/dIR8A=
+github.com/emicklei/dot v1.6.2/go.mod h1:DeV7GvQtIw4h2u73RKBkkFdvVAz0D9fzeJrgPW6gy/s=
 github.com/golang/snappy v0.0.3 h1:fHPg5GQYlCeLIPB9BZqMVR5nR9A+IM5zcgeTdjMYmLA=
 github.com/golang/snappy v0.0.3/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=
 github.com/klauspost/cpuid/v2 v2.0.4/go.mod h1:FInQzS24/EEf25PyTYn52gqo7WaD8xa0213Md/qVLRg=

tree.go

@@ -5,7 +5,10 @@ import (
 	"encoding/hex"
 	"errors"
 	"fmt"
+	"io"
 	"math"
+
+	"github.com/emicklei/dot"
 )
 
 // Proof represents a merkle proof against a general index.
@@ -86,6 +89,34 @@ type Node struct {
 	value []byte
 }
 
+func (n *Node) Draw(w io.Writer) {
+	g := dot.NewGraph(dot.Directed)
+	n.draw(1, g)
+	g.Write(w)
+}
+
+func (n *Node) draw(levelOrder int, g *dot.Graph) dot.Node {
+	var h string
+	if n.left != nil || n.right != nil {
+		h = hex.EncodeToString(n.Hash())
+	}
+	if n.value != nil {
+		h = hex.EncodeToString(n.value)
+	}
+	dn := g.Node(fmt.Sprintf("n%d", levelOrder)).
+		Label(fmt.Sprintf("%d\n%s..%s", levelOrder, h[:3], h[len(h)-3:]))
+
+	if n.left != nil {
+		ln := n.left.draw(2*levelOrder, g)
+		g.Edge(dn, ln).Label("0")
+	}
+	if n.right != nil {
+		rn := n.right.draw(2*levelOrder+1, g)
+		g.Edge(dn, rn).Label("1")
+	}
+	return dn
+}
+
 func (n *Node) Show(maxDepth int) {
 	fmt.Printf("--- Show node ---\n")
 	n.show(0, maxDepth)