ydb/yql/essentials/tests/s-expressions/suites/Casts/SafeCastOverNull.yql

(

(let config (DataSource 'config))
(let world (Configure! world config 'PureDataSource 'yt))
(let res_sink (DataSink 'result))

# Null -> Uint16
(let cast (SafeCast (Null) (DataType 'Uint16)))
(let world (Write! world res_sink (Key) cast '('('type))))

# Null -> Uint16?
(let cast (SafeCast (Null) (OptionalType (DataType 'Uint16))))
(let world (Write! world res_sink (Key) cast '('('type))))

# Just(Null) -> Null
(let cast (SafeCast (Just (Null)) (NullType)))
(let world (Write! world res_sink (Key) cast '('('type))))

# Nothing(Null?) -> Null
(let cast (SafeCast (Nothing (OptionalType (NullType))) (NullType)))
(let world (Write! world res_sink (Key) cast '('('type))))

# Uint16 -> Null
(let cast (SafeCast (Uint16 '0) (NullType)))
(let world (Write! world res_sink (Key) cast '('('type))))

# Nothing(Uint16?) -> Null
(let cast (SafeCast (Nothing (OptionalType (DataType 'Uint16))) (NullType)))
(let world (Write! world res_sink (Key) cast '('('type))))

# Null -> Null?
(let cast (SafeCast (Null) (OptionalType (NullType))))
(let world (Write! world res_sink (Key) cast '('('type))))

(let world (Commit! world res_sink))
(return world)

)