#!/usr/bin/clisp -q

;; This is an assembler preprocessor to take ARM assembly language in the
;;  format I prefer and convert it to a format suitable for
;;  input to the GNU assembler.

;; The initial conversion is to replace semicolons with at-signs.

;; We might later set up some simple renaming or substitutions.

(defun pre-process-old ()
  "Pickup the input and output file names from the command-line 
   arguments.  Copy the input to the output, but with modifications.
   To begin with, just change every occurrence of ';' to '@'.  This
   version is not used now (see the version below instead).  However,
   if our modifications become more complex, we may return to this
   version that reads a line at a time."
  (let ((input-file-name (first *args*))
        (output-file-name (second *args*)))
    (with-open-file (input-file input-file-name 
                                :direction :input
                                :element-type 'character)
      (with-open-file (output-file output-file-name
                                   :direction :output 
                                   :element-type 'character)
        (loop 
           for line = (read-line input-file nil nil)    ; get next line
           while line
           do (write-line line output-file))))))

(defun pre-process ()
  "Pickup the input and output file names from the command-line 
   arguments.  Copy the input to the output, but with modifications.
   To begin with, just change every occurrence of ';' to '@'."
  (let ((input-file-name (first *args*))
        (output-file-name (second *args*)))
    (with-open-file (input-file input-file-name 
                                :direction :input
                                :element-type 'character)
      (with-open-file (output-file output-file-name
                                   :direction :output 
                                   :element-type 'character)
        (loop 
           for char = (read-char input-file nil nil)    ; get next char
           while char
           do 
             (write-char 
              (if  (char= char #\;) #\@ char) output-file))))))


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Here is where we invoke the main function.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(pre-process)