ydb/yql/essentials/tests/s-expressions/suites/InMem/StreamFlatMap.yqls

(
#comment
(let config (DataSource 'config))

(let res_sink (DataSink 'result))
(let list (AsList (Int32 '1) (Int32 '2) (Int32 '3)))
(let world (Write! world res_sink (Key) (Collect (FlatMap (Iterator list (DependsOn (String 'A))) 
   (lambda '(x) (AsList x x)))) '('('type))))
(let add (lambda '(y) (+ y (Int32 '10))))
(let world (Write! world res_sink (Key) (Collect (FlatMap (Iterator list (DependsOn (String 'B))) 
   (lambda '(x) (Map (/ (Int32 '5) (- (Int32 '2) x)) add)))) '('('type))))
(let world (Write! world res_sink (Key) (Collect (FlatMap (Iterator list (DependsOn (String 'C))) 
   (lambda '(x) (Iterator (AsList x x))))) '('('type))))
(let world (Write! world res_sink (Key) (Collect (FlatMap list
   (lambda '(x) (Iterator (AsList x x))))) '('('type))))
(let world (Write! world res_sink (Key) (Collect (FlatMap (/ (Int32 '3) (Int32 '1))
   (lambda '(x) (Iterator (AsList x x))))) '('('type))))
(let world (Commit! world res_sink))
(return world)
)