% crochet

// -- Constructors

/// Constructs an instant from the number of milliseconds since the
/// UNIX epoch (1st January 1970, 00:00:00.000)
command #instant from-milliseconds-since-unix-epoch: (X is integer) =
  new instant(foreign instant.from-ms(X));

/// Constructs an instant from an ISO-8601 date or date-time text.
command #instant from-iso8601: (X is text) =
  new instant(foreign instant.from-iso(X));


// -- Conversions

/// Converts an instant to the number of milliseconds since the
/// UNIX epoch (1st January 1970, 00:00:00.000)
command instant to-milliseconds-since-unix-epoch -> integer =
  foreign instant.epoch-ms(self.x);

/// Converts an instant to its text representation in ISO-8601
command instant to-iso8601-text -> text =
  foreign instant.to-iso(self.x);

/// Converts an instant to a [type:plain-date-time]
command instant to-plain-date-time -> plain-date-time =
  new plain-date-time(self);


// -- Relations

/// True if two instants represent the same fixed point in time.
command instant === (That is instant) =
  self to-milliseconds-since-unix-epoch === That to-milliseconds-since-unix-epoch;

/// True if two instants DO NOT represent the same fixed point in time.
command instant =/= (That is instant) =
  self to-milliseconds-since-unix-epoch =/= That to-milliseconds-since-unix-epoch;

/// True if this instant represents an earlier fixed point in time than `That` instant.
command instant < (That is instant) =
  self to-milliseconds-since-unix-epoch < That to-milliseconds-since-unix-epoch;

/// True if this instant represents the same or an earlier fixed point in time
/// than `That` instant.
command instant <= (That is instant) =
  self to-milliseconds-since-unix-epoch <= That to-milliseconds-since-unix-epoch;

/// True if this instant represents a later fixed point in time than `That` instant.
command instant > (That is instant) =
  self to-milliseconds-since-unix-epoch > That to-milliseconds-since-unix-epoch;

/// True if this instant represents the same or a later fixed point in time than
/// `That` instant.
command instant >= (That is instant) =
  self to-milliseconds-since-unix-epoch >= That to-milliseconds-since-unix-epoch;


// -- Arithmetic

/// Forwards this instant in time by the periods described in the given [type:duration].
command instant + (That is duration) =
  #instant from-milliseconds-since-unix-epoch: (self to-milliseconds-since-unix-epoch + That to-milliseconds);

/// Moves this instant back in time by the periods described in the given [type:duration].
command instant - (That is duration) =
  #instant from-milliseconds-since-unix-epoch: (self to-milliseconds-since-unix-epoch - That to-milliseconds);