{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "test grammar for pattern properties",
  "type": "object",
  "required": [
    "rules"
  ],
  "additionalProperties": false,
  "properties": {
    "rules": {
      "type": "object",
      "patternProperties": {
        "^[a-zA-Z_]\\w*$": {
          "type": "string"
        }
      },
      "additionalProperties": false
    }
  }
}