Align matrix

(defun my/string-to-number (line re)
  (let ((matched (string-match re line)))
    (if matched
        (list (match-string 0 line)
              (substring line (length (match-string 0 line))))
      (list nil line))))

(defun my/string-to-double (line)
  (my/string-to-number
   line
   "\\s-*[+-]?[0-9]+\\(?:\\.[0-9]+\\(?:[eE][+-]?[0-9]+\\)?\\)?"))

(defun my/string-to-int (line)
  (my/string-to-number line "\\s-*[+-]?[0-9]+"))

(defun my/vector-transpose (vec)
  (cl-coerce
   (cl-loop for i below (length (aref vec 0))
            collect (cl-coerce
                     (cl-loop for j below (length vec)
                              collect (aref (aref vec j) i))
                     'vector))
   'vector))

(defun my/align-metric (col num-parser)
  (cl-loop with max-left = 0
           with max-right = 0
           with decimal = 0
           for cell across col
           for nump = (car (funcall num-parser cell))
           for has-decimals = (cl-position ?\. cell) do
           (if nump
               (if has-decimals
                   (progn
                     (setf decimal 1)
                     (when (> has-decimals max-left)
                       (setf max-left has-decimals))
                     (when (> (1- (- (length cell) has-decimals))
                              max-right)
                       (setf max-right (1- (- (length cell) has-decimals)))))
                 (when (> (length cell) max-left)
                   (setf max-left (length cell))))
             (when (> (length cell) max-left)
               (setf max-left (length cell))))
           finally (cl-return (list max-left decimal max-right))))

(defun my/print-matrix (rows metrics num-parser prefix spacer)
  (cl-loop with first-line = t
           for i upfrom 0
           for row across rows do
           (unless first-line (insert prefix))
           (setf first-line nil)
           (cl-loop with first-row = t
                    for cell across row
                    for metric in metrics
                    for has-decimals =
                    (and (cl-position ?\. cell)
                         (car (funcall num-parser cell)))
                    do
                    (unless first-row (insert spacer))
                    (setf first-row nil)
                    (cl-destructuring-bind (left decimal right) metric
                      (if has-decimals
                          (cl-destructuring-bind (whole fraction)
                              (split-string cell "\\.")
                            (insert (make-string (- left (length whole)) ?\ )
                                    whole
                                    "."
                                    fraction
                                    (make-string (- right (length fraction)) ?\ )))
                        (insert (make-string (- left (length cell)) ?\ )
                                cell
                                (make-string (1+ right) ?\ )))))
           (unless (= i (1- (length rows)))
             (insert "\n"))))

(defun my/read-rows (beg end)
  (cl-coerce
   (cl-loop for line in (split-string
                         (buffer-substring-no-properties beg end) "\n")
            collect
            (cl-coerce
             (nreverse
              (cl-loop with result = nil
                       with remaining = line do
                       (cl-destructuring-bind (num remainder)
                           (funcall num-parser remaining)
                         (if num
                             (progn
                               (push (org-trim num) result)
                               (setf remaining remainder))
                           (push (org-trim remaining) result)
                           (cl-return result)))))
             'vector))
   'vector))

(defun my/align-matrix (parser)
  (interactive "SParse numbers using: ")
  (let ((num-parser
         (cl-case parser
           (:double 'my/string-to-double)
           (:int 'my/string-to-int)
           (otherwise
            (if (functionp parser)
                parser
              'my/string-to-number))))
        beg end)
    (if (region-active-p)
        (setf beg (region-beginning)
              end (region-end))
      (setf end (1- (search-forward-regexp "\\s)" nil t))
            beg (1+ (progn (backward-sexp) (point)))))
    (goto-char beg)
    (let* ((prefix (make-string (current-column) ?\ ))
           (spacer " ")
           (rows (my/read-rows beg end))
           (cols (my/vector-transpose rows))
           (metrics
            (cl-loop for col across cols
                     collect (my/align-metric col num-parser))))
      (delete-region beg end)
      (my/print-matrix rows metrics num-parser prefix spacer))))