pub fn is_null(&self) -> bool {
        match *self {
            Value::Null => true,
            Value::List(ref list, _, false) => {
                list.iter().all(|v| v.is_null())
            }
            Value::Literal(ref s, Quotes::None) if s.is_empty() => true,
            Value::Paren(ref v) => v.is_null(),
            _ => false,
        }
    }
/// Return true if this value is null.
///
/// Note that an empty unquoted string and a list containing no
/// non-null values is also considered null.
Return true if this value is null.
Note that an empty unquoted string and a list containing no
non-null values is also considered null.
Return true if this value is null . Note that an empty unquoted string and a list containing no non - null values is also considered null .
pub fn is_null(&self) -> bool {
        match *self {
            Value::Null => true,
            Value::List(ref list, _, false) => {
                list.iter().all(|v| v.is_null())
            }
            Value::Literal(ref s, Quotes::None) if s.is_empty() => true,
            Value::Paren(ref v) => v.is_null(),
            _ => false,
        }
    }
pub fn is_null ( & self ) -> bool { match * self { Value :: Null => true , Value :: List ( ref list , _ , false ) => { list . iter ( ) . all ( | v | v . is_null ( ) ) } Value :: Literal ( ref s , Quotes :: None ) if s . is_empty ( ) => true , Value :: Paren ( ref v ) => v . is_null ( ) , _ => false , } }
Return true if this value is null.
Return true if this value is null .
&self
&self