Loop on lines in emacs (version 1)

(defmacro do-lines (args &rest body)
  (let ((line (gensym "line-"))
        (beg  (gensym "beg-"))
        (end  (gensym "end-")))
                
    `(let (,@args)
       (save-excursion
         (save-match-data
           (goto-char (point-min))
           (while (< (point) (point-max))
             (setq ,beg (point))
             (forward-line 1)
             (setq ,end (point))
             (setq ,line (buffer-substring-no-properties ,beg ,end))
             
             (setq ,(car args) ,line)
             (when ',(cdr args) (setq ,(cadr args) ,beg))
             (when ',(cddr args) (setq ,(caddr args) ,end))

             (progn ,@body)))))))

(let (lines)
  (do-lines (l b e) 
            (push (cons l e) lines))
  (reverse lines))