Support defaults via const and New() functions

[rustysys-dev]

based on the following JSONSchema I would like to propose the generation of a New() function.

{
  "definitions": {},
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "http://example.com/root.json",
  "type": "object",
  "title": "The Root Schema",
  "required": [
    "type",
    "data"
  ],
  "properties": {
    "type": {
      "$id": "#/properties/type",
      "type": "string",
      "title": "Type",
      "default": "notify_event",
      "examples": [
        "notify_event"
      ],
      "pattern": "^(.*)$"
    },
    "data": {
      "$id": "#/properties/data",
      "type": "object",
      "title": "Data",
      "required": [
        "resourceId",
        "type",
        "title",
        "content"
      ],
      "properties": {
        "resourceId": {
          "$id": "#/properties/data/properties/resourceId",
          "type": "string",
          "title": "Resourceid",
          "default": "",
          "examples": [
            "1a2s3d4f"
          ],
          "pattern": "^(.*)$"
        },
        "type": {
          "$id": "#/properties/data/properties/type",
          "type": "string",
          "title": "Type",
          "default": "rule",
          "examples": [
            "rule"
          ],
          "pattern": "^(.*)$"
        },
        "title": {
          "$id": "#/properties/data/properties/title",
          "type": "string",
          "title": "Title",
          "default": "",
          "examples": [
            "rule violation"
          ],
          "pattern": "^(.*)$"
        },
        "content": {
          "$id": "#/properties/data/properties/content",
          "type": "string",
          "title": "Content",
          "default": "",
          "examples": [
            "some explaination about rule violation"
          ],
          "pattern": "^(.*)$"
        }
      }
    }
  }
}

Proposed Output:

package main

const (
	defaultType     string = "notify_event"
	defaultDataType string = "rule"
)

type schema struct {
	Data theData `json:"data"`
	Type string  `json:"type"`
}

type data struct {
	Content    string `json:"content"`
	Resourceid string `json:"resourceId"`
	Title      string `json:"title"`
	Type       string `json:"type"`
}

func NewSchema() *schema {
	return &schema{
		Data: data{
			Content:    "",
			Resourceid: "",
			Title:      "",
			Type:       defaultDataType,
		},
		Type: defaultType,
	}
}

func NewData() *data {
	return &data{
		Content:    "",
		Resourceid: "",
		Title:      "",
		Type:       defaultDataType,
	}
}