macro
boot.janet on line 1411 , column 1
( x & forms )
Short circuit threading macro. Inserts x as the second value in the
first form in `forms` , and inserts the modified first form into the
second form in the same manner , and so on. The pipeline will return
nil if an intermediate value is nil. Useful for expressing
pipelines of data.
(defn return-nil [x ] nil )
( 1 inc ) # -> 2
( 1 inc inc ) # -> 3
( 1 inc inc return-nil ) # -> nil
( 1 inc inc return-nil inc ) # -> nil