createTypedQuantityInstance function

Quantity createTypedQuantityInstance(Type t, dynamic value, Units? units, { double uncert = 0.0, Dimensions? dimensions, })

Creates an instance of a typed quantity of type t having the specified value in units.

If type t is not recognized a MiscQuantity with value and the dimensions of units will be created and returned instead. If units are null and the the type is not recognized, then dimensions must be provided in order to construct a MiscQuantity. A DimensionsException will be thrown if null units and null dimensions are detected for types that don't have an associated instantiator.

The quantity's relative uncertainty can optionally be provided (defaults to 0).

Implementation

Quantity createTypedQuantityInstance(Type t, dynamic value, Units? units,
    {double uncert = 0.0, Dimensions? dimensions}) {
  final quantityInstantiator = _typeInstantiatorMap[t];
  if (quantityInstantiator != null) {
    return Function.apply(quantityInstantiator, <dynamic>[value, units, uncert])
        as Quantity;
  }

  // Fall back to MiscQuantity.
  if (dimensions == null && units == null) {
    throw DimensionsException(
        'Dimensions must be provided if units are not when creating an instance of an unrecognized quantity type');
  }
  return MiscQuantity(value, (units as Quantity).dimensions, uncert);
}