RosettaCodeData/Task/String-length/Bracmat/string-length-3.bracmat

(CharacterLength=
  length c p
.     0:?length:?p
    & @( !arg
       :   ?
           ( [!p %?c
           & utf$!c:?k
           & 1+!length:?length
           )
           ([?p&~)
           ?
       )
  | !length
);