RosettaCodeData/Task/Time-a-function/Bracmat/time-a-function.bracmat

( ( time
  =   fun funarg t0 ret
    .   !arg:(?fun.?funarg)
      & clk$:?t0
      & !fun$!funarg:?ret
      & (!ret.flt$(clk$+-1*!t0,3) s)
  )
& ( fib
  =
    .   !arg:<2&1
      | fib$(!arg+-1)+fib$(!arg+-2)
  )
& time$(fib.30)
)