{

  "$schema":       "http://json-schema.org/draft-06/schema#",

  "id":            "http://www.iucr.org/resources/cif/cif-json.json",

  "description":   "The CIF-JSON top-level object",

  "type":          "object",

  "required":      ["CIF-JSON"],

  "maxProperties": 1,

  "properties":    {

    "CIF-JSON":      {

      "description":              "The CIF-JSON object",

      "type":                     "object",

      "patternProperties":        {

        "^[^A-Z\u0000-\u0020]+$":       {

          "id":                       "#datablock",

          "title":                    "datablock",

          "description":              "An object representing a CIF datablock",

          "type":                     "object",

          "patternProperties":        {

            "^_[^A-Z\u0000-\u0020]+$":      {

              "title":                    "values",

              "description":              "An array of all the values taken by a CIF data item",

              "type":                     "array",

              "minItems":                 1,

              "items":                    {

                "id":                       "#datavalue",

                "title":                    "datavalue",

                "description":              "A CIF data value",

                "anyOf":                    [

                  {

                    "title":                  "string / number",

                    "description":            "A CIF string or numeric value",

                    "type":                   "string"

                  },

                  {

                    "title":                  "null",

                    "description":            "A CIF null value (.)",

                    "type":                   "boolean",

                    "const":                  false

                  },

                  {

                    "title":                  "unknown",

                    "description":            "A CIF unknown value (?)",

                    "type":                   "null"

                  },

                  {

                    "title":                  "list",

                    "description":            "A CIF list value",

                    "type":                   "array",

                    "items":                  { "$ref": "#datavalue" }

                  },

                  {

                    "title":                  "table",

                    "description":            "A CIF table value",

                    "type":                   "object",

                    "additionalProperties":   { "$ref": "#datavalue" }

                  }

                ]

              }

            }

          },

          "properties":           {

            "Frames":               {

              "type":                 "object",

              "patternProperties":    {

                "^[^\u0000-\u0020A-Z]+$":   { "$ref": "#datablock" }

              },

              "additionalProperties": { "not": {} }

            }

          },

          "additionalProperties": { "not": {} }

        }

      },

      "properties": {

        "Metadata":   {

          "description": "provides instance metadata",

          "type":        "object",

          "properties":  {

            "cif-version":    {

              "type":           "string",

              "enum":           ["1.1", "2.0"],

              "description":    "The version of CIF with which the content of this CIF-JSON instance conforms"

            },

            "schema-name":    {

              "type":           "string",

              "const":          "CIF-JSON",

              "default":        "CIF-JSON",

              "description":    "Identifies the JSON format of this instance's content; always 'CIF-JSON' for instances conforming to this schema"

            },

            "schema-version": {

              "type":           "string",

              "pattern":        "(0|[1-9][0-9]*)[.](0|[1-9][0-9]*)[.](0|[1-9][0-9]*)",

              "description":    "The version of CIF-JSON to which this instance conforms, in dotted-triplet form; CIF-JSON version numbers are assigned according to semantic versioning principles"

            },

            "schema-uri":     {

              "type":           "string",

              "const":          "http://www.iucr.org/resources/cif/cif-json.json",

              "default":        "http://www.iucr.org/resources/cif/cif-json.json",

              "description":    "A URI (in fact a URL) specifying the location of this schema"

            }

          }

        }

      }

    }

  }

}