expr

type LeafValidator struct {
	Name string
	Args []string
	Msg  string

	Param Param
	Decls []*decl.Validator
}

type LogicValidator struct {
	Qualifier string
	Name      string
	Left      Validator
	Right     Validator // `Not` has no Right validator.
}

type Param struct {
	Name string
	Type types.Type
}

type Parser struct {
	S string
}

type Validator interface {
	Bind(param Param, decls map[string][]*decl.Validator) error

	// ExprString returns the validating-style expression string.
	ExprString() string
}