如何在Emacs VHDL模式下对齐某些文本

Question

In Emacs how would I align a group of text:

signal slv4   : std_logic_vector(3 downto 0);
signal slv16  : std_logic_vector(15 downto 0);
signal slv8   : std_logic_vector(7 downto 0);
signal slv32  : std_logic_vector(32 downto 0);

so it looks like this

signal slv4   : std_logic_vector( 3 downto 0);
signal slv16  : std_logic_vector(15 downto 0);
signal slv8   : std_logic_vector( 7 downto 0);
signal slv32  : std_logic_vector(32 downto 0);

Basically I want to right justify the numbers before "downto"; another side effect is that the text is right justified (the semi-colons line up).

How would I achieve this? I have played around with Mx align and Mx align-regexp however I can't seem to get what I'm looking for.

Also I'm using vhdl-mode so maybe it has something built in?

Answer 1

I don't think there is such a thing in vhdl mode because you need spaces in the middle of the text. If it were just about right aligning, you could possibly play around with tab behaviour. In this case, you could use a macro.

http://www.emacswiki.org/emacs/KeyboardMacros

Answer 2

In a first run the maximum of padding is detected, than called recursively with padding given.

Edit `this-regexp' inside let if something different is needed. Maybe the hard-coded opening "(" in concat-form needs edit than too.

(defun my-numbers-padded (&optional beg end len)
  "Pad numbers as given in example string "
  (interactive "*")
  (let* ((beg (cond (beg)
                    ((use-region-p)
                     (region-beginning))
                    (t (point-min))))
         (end (cond (end (copy-marker end))
                    ((use-region-p)
                     (copy-marker (region-end)))
                    (t (copy-marker (point-max)))))
         (this-regexp "^\\([^(]+\\)\(\\([0-9]+\\)\\(.+\\)$")
         (len len)
         lenmax
         (var (and len (concat "(format \"%" (number-to-string len) "s\" (match-string-no-properties 2))"))))
    (goto-char beg)
    (if len
        (while (re-search-forward this-regexp  nil t 1)
          (setq erg (eval (car (read-from-string var))))
          (replace-match
           (concat (match-string-no-properties 1) "\("   erg (match-string-no-properties 3))))
      (while (re-search-forward this-regexp  nil t 1)
        (setq current-length (length (match-string-no-properties 2)))
        (if (and lenmax (< lenmax current-length))
            (setq lenmax current-length)
          (unless lenmax (setq lenmax current-length))))
      (my-padding-numbers beg end lenmax))))

Answer 3

Here is what I'm currently using (which works fine):

(defun my-align-downto (beg end)
    (interactive "r")
    (align-regexp beg end "\\([0-9]* downto*\\)" -1 0 t))

I thought I would take it one step further and create my own 'align hook' based on the information at the very bottom of this page: http://www.emacswiki.org/emacs/AlignCommands#toc8

(add-hook 'align-load-hook (lambda ()
    (add-to-list 'align-rules-list
      '(downto-align
        (regexp  . "\\([0-9]* downto*\\)")
        (group   . -1)
        (spacing . 0)
        (modes   . vhdl-mode)
        (repeat  . t)))))

With which I get no results. :(

Does vhdl-mode override these alignment rules.. or am I just not doing something correctly?