var (
	// Schema is the standard profile used for comparing schema.
	Schema = &Profile{}

	// Final is the standard profile for comparing data.
	Final = &Profile{
		Concrete: true,
	}
)

type Edit struct {
	Kind Kind
	XSel cue.Selector // valid if UniqueY
	YSel cue.Selector // valid if UniqueX
	Sub  *EditScript  // non-nil if Modified
}

type EditScript struct {
	X, Y  cue.Value
	Edits []Edit
}

type Kind uint8

const (
	// Identity indicates that a value pair is identical in both list X and Y.
	Identity Kind = iota
	// UniqueX indicates that a value only exists in X and not Y.
	UniqueX
	// UniqueY indicates that a value only exists in Y and not X.
	UniqueY
	// Modified indicates that a value pair is a modification of each other.
	Modified
)

type Profile struct {
	Concrete bool

	// Hidden fields are only useful to compare when a values are from the same
	// package.
	SkipHidden bool
}