-?>>

    macro
    boot.janet on line 1163, column 1

    (-?>> x & forms)

    Short circuit threading macro. Inserts x as the last 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.