count.l

(define aux (load "aux.l"))

(define count-indexed (name)
  (let h ((get io 'open) name)
    ((get h 'seek) h "end" -8)
    (with n (tonumber (be64dec ((get h 'read) h "*a")))
      ((get h 'close) h))))

(define count-rows (name)
  (let h ((get io 'open) name)
    (with i 0
      (while true
        (define line ((get h 'read) h "*l"))
        (unless line (break))
        (unless (or (= line "") (= line "\r"))
          (inc i)))
      ((get h 'close) h))))

(define count (name)
  (if (file-exists? (cat name ".idx"))
      (count-indexed (cat name ".idx"))
    (count-rows name)))

(define name (at argv 1))
(define n (count name))
(dec n) ; skip the CSV header.
(print n)