The list of UserName homepages found on the CategoryHomepage article can be maintained using a few Emacs commands. The commands convert the list to a one-name-per-line list that can then be easily alphabetized with ‘M-x sort-regexp-fields’ and uses the Unix ‘uniq’ command to filter out duplicates (Yes, it requires a GNU or Unix-like system). More commands convert the list back to Wiki syntax.

To convert the list, as it is, in to a one-per line list can be done roughly with the following in Emacs:

  M-% , C-o RET C-o RET !
  M-% , SPC RET C-o RET !
  M-% * SPC RET RET !

It can then be lexicographically alphabetized with the following:

  C-x h
  M-x set-variable RET sort-fold-case RET t RET
  M-x sort-regexp-fields RET ^\[*\(.*\)\]*$ RET \1 RET

You can narrow it to unique entries with:

  C-x h M-| uniq RET

To convert the list of usernames back to its Wiki list can be done with some EmacsLisp (Alternatively, this intermediate format could become the permanent format for the page):

    (goto-char (point-min))
    (insert "* ")
    (while (search-forward-regexp "\\[*\\(\\w\\).*\n\\(\\[*\\(\\1\\).*\n\\)*" (point-max) t)
      (insert "* "))
    (goto-char (point-min)))

and some SearchAndReplace commands:

  M-% C-o RET , SPC RET !
  M-% SPC * SPC RET C-q C-j * SPC RET !

The recipe above for sorting and converting the UserName list back to Wiki syntax is consolidated into a single snippet of Lisp code.

    (defun emacswiki-alphabetize-homepage-list (beg end)
      "Alphabetize the EmacsWiki homepage list in the current region."
      (interactive "r")
        ;; Rather than narrow-to-region, use markers.
        (let ((end-mark (copy-marker end)))
          ;; Remove "* " at the beginning of lines.
          (goto-char beg)
          (while (re-search-forward "^\\*\\s-*"
                                    (marker-position end-mark) t)
            (replace-match ""))
          ;; Put everything between commas on its own line.
          (goto-char beg)
          (while (re-search-forward ",[ \n]*"
                                    (marker-position end-mark) t)
            (replace-match "\n"))
          ;; Alpha sort all the homepage links on each line.
          (goto-char beg)
          (let ((sort-fold-case t))
            (sort-regexp-fields nil "^\\[*\\(.*\\)\\]*$" "\\1" beg
                                (marker-position end-mark)))
          ;; Keep only unique lines.  Based on uniquify on EmacsWiki.
          (goto-char beg)
          (while (re-search-forward "^\\(.*\n\\)\\1+"
                                    (marker-position end-mark) t)
            (replace-match "\\1"))
          (message "There are %d entries"
                   (count-lines beg (marker-position end-mark)))
          ;; Put "* " at beginning,
          (goto-char beg)
          (insert "* ")
          ;; and at the beginning of each letter in the alphabet.
          (while (and (re-search-forward "\\[*\\(\\w\\).*\n\\(\\[*\\(\\1\\).*\n\\)+"
                                         (marker-position end-mark) t)
                      (> (marker-position end-mark)
                         (point))) ;; Error if search started after `end-mark'.
            (insert "* "))
          ;; Put commas between lines not starting with "* "
          (goto-char beg)
          (while (re-search-forward "\n"
                                         (marker-position end-mark) t)
            (if (and (not (looking-at "* "))
                     (> (marker-position end-mark)
                (replace-match ", "))))))