   }
 
   /// Look for the precedence group corresponding to the given operator.
-  public func lookupOperatorPrecedenceGroup(
+  func lookupOperatorPrecedenceGroup(
     _ operatorName: OperatorName
   ) throws -> PrecedenceGroup? {
     guard let groupName = try lookupOperatorPrecedenceGroupName(operatorName)

  ///
  /// Follow the precedence relationships among the precedence groups to
  /// determine the precedence of the start group relative to the end group.
  public func precedence(
    relating startGroupName: PrecedenceGroupName,
    to endGroupName: PrecedenceGroupName
  ) throws -> Precedence {


  /// Look for the precedence group with the given name, or produce an error
  /// if such a group is not known.
  func lookupGroup(
    _ groupName: PrecedenceGroupName
  ) throws -> PrecedenceGroup {
    guard let group = precedenceGroups[groupName] else {
