(

(library "alterto.yql")
(import alterto_module '"alterto.yql")

(let config (DataSource 'config))

# Null -> Uint16?
(let targetType (OptionalType (DataType 'Uint16)))
(let world (Apply (bind alterto_module 'doAlterTo) world (Null) targetType (Just (Uint16 '12345))))

# Just(Null) -> Null
(let alterToResult (AlterTo (Just (Null)) (NullType) (lambda '(x) (String 'OK)) (String 'FAIL)))
(let res_sink (DataSink 'result))
(let world (Write! world res_sink (Key) alterToResult '('('type))))

# Nothing(Null?) -> Null
(let alterToResult (AlterTo (Nothing (OptionalType (NullType))) (NullType) (lambda '(x) (String 'OK)) (String 'FAIL)))
(let res_sink (DataSink 'result))
(let world (Write! world res_sink (Key) alterToResult '('('type))))

# Nothing(Uint16?) -> Null
(let alterToResult (AlterTo (Nothing (OptionalType (DataType 'Uint16))) (NullType) (lambda '(x) (String 'OK)) (String 'FAIL)))
(let res_sink (DataSink 'result))
(let world (Write! world res_sink (Key) alterToResult '('('type))))

# Null -> Null?
(let alterToResult (AlterTo (Null) (OptionalType (NullType)) (lambda '(x) (String 'OK)) (String 'FAIL)))
(let res_sink (DataSink 'result))
(let world (Write! world res_sink (Key) alterToResult '('('type))))

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

)