gistfile1.dylan

define method newtons-sqrt (x :: <number>)
   local method sqrt1 (guess)
           // note call to other local method
           if (close-enough? (guess))
              guess
           else
              sqrt1 (improve (guess))  // note self-recursive call
           end if
         end sqrt1,
         method close-enough? (guess)
           abs (guess * guess - x) < .0001
         end close-enough?,
         method improve (guess)
           (guess + (x / guess)) / 2
         end improve;
    sqrt1 (1)
end method newtons-sqrt;