extension PureYAML.Parsing.LibYAML {
    /// A scanner token kind, mirroring `yaml_token_type_t`. Only the structural
    /// kinds the indentation engine produces are modelled here; scalar, anchor,
    /// tag, and document kinds are added as their fetchers are ported.
    enum TokenType: Equatable {
        case blockSequenceStart
        case blockMappingStart
        case blockEnd
    }
}