Added a simple implementation of structs in lisp, using just a macro and a few functions

asd.lisp

@@ -0,0 +1,31 @@
+(progn
+  (defun add (a b) (+ a b))
+  (defvar whatever 16))
+
+;; struct
+(progn 
+  (defun constructor-name (sym)
+    (intern (concatenate 'string "MAKE-" (string sym))))
+
+  (defun accessor-name (name sym)
+    (intern (concatenate 'string (string name) "-" (string sym))))
+
+  (defun setter-name (name sym)
+    (intern (concatenate 'string "SET-" (string name) "-" (string sym))))
+
+  (defmacro mydefstruct (name &rest slots)
+    `(progn
+       (defun ,(constructor-name name)
+	 ,slots
+	 (list ,@slots))
+       ,@(loop for i from 0 to (1- (length slots)) collect
+	       `(defun ,(accessor-name name (nth i slots))
+		    (instance)
+		  (nth ,i instance)))
+       ,@ (loop for i from 0 to (1- (length slots)) collect
+		`(defun ,(setter-name name (nth i slots))
+		     (instance val)
+		   (setf (nth ,i instance) val)))
+       ,@(loop for i from 0 to (1- (length slots)) collect
+	       `(defsetf ,(accessor-name name (nth i slots))
+		    ,(setter-name name (nth i slots)))))))