{
  "name": "feature_id",
  "type": "function",
  "groups": ["Record and Attributes"],
  "description": "Returns a feature's unique ID, or NULL if the feature is not valid.",
  "arguments": [{
    "arg": "feature",
    "description": "a feature object"
  }],
  "examples": [{
    "expression": "feature_id( @feature )",
    "returns": "the ID of the current feature"
  }],
  "tags": []
}