concatenate -> concat

gistfile1.lisp

(defun concat (type &rest items)
  (let* ((len (loop for e in items
                    if (typep e 'sequence)
                    sum (length e)
                    else sum 1))
         (seq (make-sequence type len)))
    (loop with pos = 0
          for e in items
          if (typep e 'sequence)
          do (progn
               (setf (subseq seq pos) e)
               (incf pos (length e)))
          else
          do (progn
               (setf (elt seq pos) e)
               (incf pos)))
    seq))