internal

type Directive struct {
	Prefixes []string // "each" and "key" prefixes, outermost first
	Name     string   // "notzero", "trim", "tolower", "toupper", "len", "val", "oneof", "regexp", "default", "delegate", "on", "-", or the verbatim text of an unrecognized directive
	Operator string   // the comparison operator of a "len" or "val" directive
	Value    string   // the operand: the bound, pattern, set of values, default value, or field name
}

type Validator interface {
	Validate(ctx context.Context) error
}