Syntactic motif offsets (Lisp baseline)

motif-offsets.lisp

(defun indices (input-file output-file)
  (with-open-file (in input-file :direction :input)
    (with-open-file (out output-file :direction :output
                                     :if-exists :supersede
                                     :if-does-not-exist :create)
      (loop with previous-field = nil
            for index from 0
            for field = (read in nil nil)
            while field
            if (not previous-field)
              do (format out "0")
            else if (<= field previous-field)
              do (format out " ~w" index)
            do (setq previous-field field)))))