{
  "name": "attribute",
  "type": "function",
  "description": "Returns the value of a specified attribute from a feature.",
  "arguments": [ {"arg":"feature","description":"a feature"},
                 {"arg":"attribute_name","description":"name of attribute to be returned"}],
  "examples": [ { "expression":"attribute( $currentfeature, 'name' )", "returns":"value stored in 'name' attribute for the current feature"}]
}