Change API parser to handle nested objects (#159)

* rewrite parser to handle new format and nested objects

* add properties section also to nested properties

* update docs manually

generator/expandOpenAPIRef.go

@@ -0,0 +1,61 @@
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	"github.com/pb33f/libopenapi/index"
+	"gopkg.in/yaml.v3"
+)
+
+func main() {
+
+	// if len(os.Args) != 1 {
+	// 	fmt.Printf("No input file provided!\n")
+	// }
+
+	// load an OpenAPI 3 specification from bytes
+	// petstore, _ := ioutil.ReadFile(os.Args[0])
+	petstore, _ := ioutil.ReadFile("openapi/openapi.yml")
+
+	// create a root node to unmarshal the spec into.
+	var rootNode yaml.Node
+	_ = yaml.Unmarshal(petstore, &rootNode)
+
+	// create a new config that does not allow lookups.
+	indexConfig := index.CreateClosedAPIIndexConfig()
+
+	// create a new rolodex
+	rolodex := index.NewRolodex(indexConfig)
+
+	// set the rolodex root node to the root node of the spec.
+	rolodex.SetRootNode(&rootNode)
+
+	// index the rolodex
+	indexedErr := rolodex.IndexTheRolodex()
+	if indexedErr != nil {
+		panic(indexedErr)
+	}
+
+	// resolve the petstore
+	rolodex.Resolve()
+
+	// extract the resolver from the root index.
+	node := rolodex.GetRootNode()
+
+	b, e := yaml.Marshal(node)
+	if e != nil {
+		panic(e)
+	}
+
+	var newNode yaml.Node
+	_ = yaml.Unmarshal(b, &newNode)
+
+	err := os.WriteFile("openapi/expanded.yml", b, 0644)
+	if err != nil {
+		fmt.Printf("Failed to write file: %v", err)
+		return
+	}
+
+}