(

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

(let config (DataSource 'config))

(let targetType (StructType '('"a" (DataType 'Uint8)) '('"b" (DataType 'Utf8))))
(let failValue (AsStruct '('a (Uint8 '0)) '('b (Utf8 '"not converted"))))

# Struct<Int32, String> -> Struct<Uint8, Utf8>
(let value (AsStruct '('a (Int32 '1)) '('b (String 'one))))
(let world (Apply (bind alterto_module 'doAlterTo) world value targetType failValue))

# Struct<Int32, String> -> Struct<Uint8, Utf8> (fail)
(let value (AsStruct '('a (Int32 '"-1")) '('b (String 'one))))
(let world (Apply (bind alterto_module 'doAlterTo) world value targetType failValue))

(return world)

)