ydb/yql/essentials/tests/s-expressions/suites/Optimizers/Fold1OneItemStruct.yqls

(
(let config (DataSource 'config))

(let list (AsList (String 'a) (String 'b) (String 'c)))
(let data (Fold1 list
   (lambda '(item)
       (AddMember 
          (Struct) 
          'z 
          item))
   (lambda '(item state) 
       (AddMember 
          (Struct) 
          'z 
          (Concat (Member state 'z) item)))))
(let res_sink (DataSink 'result))
(let world (Write! world res_sink
    (Key)
    data '('('type))))

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