FVariantOperation<K extends FVariantConstraint, E extends FVariant, V, D extends Delta>.exact constructor

FVariantOperation<K extends FVariantConstraint, E extends FVariant, V, D extends Delta>.exact(Set<K> constraints, D delta)

Applies delta to the base and associates the result with each constraint in constraints.

Unlike FVariantOperation.match, this creates exact entries rather than matching existing variants.

// Given base: 0, {a: 1, b: 1}
.exact({b, c}, Delta(2)) // {a: 1, b: 2, c: 2}

See also:

• FVariantOperation.match for applying to variants whose constraint's variants are all present.
• FVariantOperation.base for applying to the base.
• FVariantOperation.variants for applying to all variants.
• FVariantOperation.all for applying to all variants and base.

Implementation

FVariantOperation.exact(Set<K> constraints, D delta)
  : _call = ((base, existing) {
      final addition = delta(base) as V;
      return .raw(base, {...existing, for (final constraint in constraints) constraint: addition});
    });