tree-sitter/test/fixtures/test_grammars/epsilon_rules/grammar.json

{
  "name": "epsilon_rules",

  "rules": {
    "rule_1": {"type": "SYMBOL", "name": "rule_2"},

    "rule_2": {
      "type": "CHOICE",
      "members": [
        {"type": "SYMBOL", "name": "rule_1"},
        {"type": "BLANK"}
      ]
    }
  }
}