Add function for retrieve start node and neighboor of given node

cmd/resolve.go

@@ -37,4 +37,13 @@ func main() {
 	for _, p := range graph.Nodes {
 		fmt.Printf("%+v\n", p)
 	}
+
+	start, err := graph.GetStartingNode()
+	fmt.Printf("%#v\n", start)
+
+	fmt.Printf("neighbourNode of %+v : \n", start)
+	neig := graph.GetNeighbour(start)
+	for _, n := range neig {
+		fmt.Printf("%+v\n", n)
+	}
 }

graph.json

@@ -0,0 +1,28 @@
+{
+  "graph": [
+    {
+      "links": [
+        {
+          "from": "A",
+          "oriented": false,
+          "to": "B",
+          "value": 10
+        }
+      ],
+      "name": "graph1",
+      "nodes": [
+        {
+          "name": "A",
+          "start": true
+        },
+        {
+          "name": "B",
+          "value": 0
+        },
+        {
+          "name": "A"
+        }
+      ]
+    }
+  ]
+}

internal/graph.go

@@ -10,3 +10,33 @@ type Graph struct {
 	Links []*Link `hcl:"links,block"`
 }
 
+func (g *Graph) GetStartingNode() (Node, error) {
+	for i := 0; i < len(g.Nodes); i++ {
+		n := (*g.Nodes[i])
+		if n.IsStart == true {
+			return n, nil
+		}
+	}
+	return Node{}, errors.New("No start node found")
+}
+
+func (g *Graph) GetNeighbour(n Node) []Node {
+	var neighbourNodeName []string
+	for i := 0; i < len(g.Links); i++ {
+		if g.Links[i].From == n.Name {
+			neighbourNodeName = append(neighbourNodeName, g.Links[i].To)
+		}
+	}
+
+	// create temporary map of node by here name for direct future access
+	var nodeByName = make(map[string]Node)
+	for i := 0; i < len(g.Nodes); i++ {
+		nodeByName[g.Nodes[i].Name] = (*g.Nodes[i])
+	}
+
+	var neighbourNode = make([]Node, len(neighbourNodeName))
+	for i := 0; i < len(neighbourNodeName); i++ {
+		neighbourNode[i] = nodeByName[neighbourNodeName[i]]
+	}
+	return neighbourNode
+}