public < R1 , R4 > Writer < W , R4 > forEach2 ( Function < ? super T , Writer < W , R1 > > value2 , BiFunction < ? super T , ? super R1 , ? extends R4 > yieldingFunction ) { return this . flatMap ( in -> { Writer < W , R1 > a = value2 . apply ( in ) ; return a . map ( in2 -> { return yieldingFunction . apply ( in , in2 ) ; } ) ; } ) ; }
Perform a For Comprehension over a Writer accepting a generating function . This results in a two level nested internal iteration over the provided Writers .