delta.go

package yin

// Delta is the non-generic public seam for document catch-up payloads.
//
// A Delta implementation must carry all state needed to reconstruct and apply
// the represented document update for its concrete CRDT kind. The interface is
// intentionally small: Kind identifies the concrete delta family for routing or
// a future codec, and Version describes the causal state covered by the delta.
// Yin does not define a concrete wire encoding here; codecs should translate
// concrete delta implementations at this seam without changing Document.
type Delta interface {
	// Kind returns a stable type tag for the concrete delta family.
	//
	// ApplyDelta implementations and future serialization codecs use this tag to
	// route heterogeneous deltas without making the public Delta interface
	// generic. Kind is not itself a wire format.
	Kind() string

	// Version returns the causal state fully represented by this delta.
	//
	// The returned VersionVector lets receivers and codecs reason about catch-up
	// coverage while the concrete delta still owns its reconstructable payload.
	Version() VersionVector
}