{def longest_string
 {def longest_string.r
  {lambda {:max :s}
   {if {S.empty? {S.rest :s}}
    then
    else {if {= {W.length {S.first :s}} :max} then {br}{S.first :s} else}
         {longest_string.r :max {S.rest :s}}}}}
 {lambda {:s}
  {longest_string.r {max {S.map W.length :s}} :s #}}}
-> longest_string

{def words a bb ccc ddd ee f ggg}  // it's a sentence, not a list
-> words

{longest_string {words}}
->
ccc
ddd
ggg