transcendental-lisp/lisp/random/array.lisp

(let ((static))

  (setq static
    (dlambda
      (:create-indices (length)
        (call static :create-indices-tail (- length 1) ()))

      (:create-indices-tail (index accumulator)
        (if (< index 0)
          accumulator
          (recur (- index 1) (cons index accumulator))))))

  (defmacro array (length)
    (let* ((this (gensym))
           (index-prefix (fuse this 'index))
           (indices (call static :create-indices length))
           (index-bindings (map (lambda (i) `(,(fuse index-prefix i))) indices))
           (scope `((,this) ,@index-bindings)))

      `(let ,scope
        (setq ,this
          (dlambda
            (:get (i)
              (eval (fuse ',index-prefix i)))

            (:set (i value)
              (if (and (< i ,length) (> i -1))
                (set (fuse ',index-prefix i) value)
                (call ,this :get i))) ;; show error

            (:length ()
              ,length)

            (t ()
              ((lambda (length accumulator)
                 (if (< length 1)
                   accumulator
                   (recur
                     (- length 1)
                     (cons (call ,this :get (- length 1)) accumulator))))
               ,length nil))))))))