- The value of a terminal cannot be another expression.
Is this a necessary restriction?
Not really; I probably put that restriction there due to lack of imagination. Terminals' values should be treated as simple types, but there's no real reason those types can't happen to model Expression.
Is this a necessary restriction?
Not really; I probably put that restriction there due to lack of imagination. Terminals' values should be treated as simple types, but there's no real reason those types can't happen to model Expression.