CounterStyle.defineCustomAlgorithm constructor

CounterStyle.defineCustomAlgorithm({ required String name, String negative = '', String prefix = '', String suffix = '\u002E\u0020', required String algorithm(int), required IntRange range, int padLength = 0, String padCharacter = '', String fallback = 'decimal', })

Implementation

factory CounterStyle.defineCustomAlgorithm({
  /// The name of the system. Not used internally, but could be used in a
  /// list of CounterStyle's to lookup a given style.
  required String name,

  /// The character to prepend to negative values.
  /// If not specified, this system won't use a negative sign
  String negative = '',
  // TODO add negativeSuffix

  /// A prefix to add when generating marker content
  String prefix = '',

  /// A suffix to add when generating marker content (Defaults to
  /// a full stop followed by a space: ". ").
  String suffix = '\u002E\u0020',

  /// The custom algorithm to apply when generating marker or counter
  /// content from this style.
  required String Function(int) algorithm,

  /// The range of values this CounterStyle can accept. If a counter value is
  /// given outside of this range, then the CounterStyle will fall back on
  /// the CounterStyle defined by [fallback].
  required IntRange range,

  /// The length each output must have at minimum, including negative symbols, but not
  /// including any suffix or prefix symbols.
  /// padLength must be greater than or equal to 0.
  int padLength = 0,

  /// The character with which to pad the output to reach the given padLength.
  /// If more than one character is given in [padCharacter], then the output
  /// will be longer than [padLength] (but never shorter).
  String padCharacter = '',

  /// The CounterStyle to fall back on if the given algorithm can't compute
  /// an output or is given out-of-range input.
  String fallback = 'decimal',

  //TODO speak-as descriptor (https://www.w3.org/TR/css-counter-styles-3/#counter-style-speak-as)
}) {
  assert(padLength >= 0);

  return CounterStyle._(
    name: name,
    algorithm: algorithm,
    negative: negative,
    prefix: prefix,
    suffix: suffix,
    range: range,
    padLength: padLength,
    padCharacter: padCharacter,
    usesNegative: negative.isNotEmpty,
    fallbackStyle: fallback,
  );
}