;; -*- mode: common-lisp -*-
#|
clasm-6502: An assembler for the 6502 written in Common Lisp.
Copyright (C) 2024  Aleksei Eaves

This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
|#

(defun last-char (s)
  (char s (- (length s) 1)))

(setf
 *grammar*
 '((label
	(lambda (l)
	  (eq (last-char (first l)) #\:)))
   (macro
	(lambda (l)
	  (eq (second l) "=")))
   (attribute
	(lambda (l)
	  (eq (char (first l) 0) #\.)))
   (instruction
	(lambda (l)
	  (if (or (member (read-from-string (first l)) *opcodes*)
			  (member (read-from-string (second l)) *opcodes*))
		  t nil)))))


(defun syntax-rule (item list)
  "Test a line against a list of syntax rules."
  (dolist (i (extract-keys list))	
	(let ((z (funcall
			  (eval (cadr (assoc i list)))
			  item)))
	  (cond ((not (equal
				   z nil))
			 (return i))
			(t nil)))))

(syntax-rule '("LDA:" "$05") *grammar*)