[ANN] List improvement v.2

* [ANN] List improvement v.2
@ 2010-07-22 21:08 Nicolas Goaziou
  2010-07-23  7:55 ` Nicolas Goaziou
                   ` (7 more replies)
  0 siblings, 8 replies; 56+ messages in thread
From: Nicolas Goaziou @ 2010-07-22 21:08 UTC (permalink / raw)
  To: Org Mode List

Hello,

Here is a new, and probably final feature-wise, suggestion of list
improvement in Org Mode.

Table of Contents
=================
1 What is it about again ? 
2 Is that all ? 
    2.1 Preserving blank lines 
    2.2 Timer lists 
    2.3 Automatic rules 
    2.4 `org-apply-on-list' 
3 Where can it be tried ? 

1 What is it about again ? 
~~~~~~~~~~~~~~~~~~~~~~~~~~~

  I redefined lists in Org Mode. Lists start, as before, at a bullet
  (whose true regexp is at `org-item-beginning-re'), and end at either
  `org-list-end-regexp', a new headline, or, obviously, end of buffer.

  `org-list-end-regexp' is customizable and defaults to 2 blank lines,
  but `org-empty-line-terminates-plain-lists' has precedence over it.
  Moreover, any `org-list-end-regexp' found in special blocks does not
  end list. Here are two examples of valid lists:

  Case 1: `org-list-end-regexp' is at default value

  - First item

    - Sub item

      #+BEGIN_EXAMPLE
      Two blank lines below

      Two blank lines above
      #+END_SRC

    - Last sub item

  List has ended at the beginning of this line.

  Case 2: `org-list-end-regexp' is "^[ \t]*___[ \t]*\n"

  - item 1
  - item 2
    - sub-item
    - sub-item 2
  - item 3
  __
  List has ended at the beginning of this line.

  Now, Org Mode knows when a list has ended and how to indent line
  accordingly. In other words, you can `org-return-indent' three times
  to exit a list and be at the right column to go on with the text.

  This new definition is also understood by exporters (LaTeX, DocBook,
  HTML or ASCII) and `org-list-end-regexp' will appear in source as a
  blank line, whatever its value is (as long as it starts with a caret
  and ends with a newline character, as specified in doc-string).

  Another advantage is that you can have two lists of different types
  in a row like in the example below:

  - item
  - item

  1. item
  2. item

  In this example, you can move (or cycle, or indent) items in the
  second list without worrying about changing the first one.

2 Is that all ? 
~~~~~~~~~~~~~~~~

  Yes and no. I tried as much as possible to keep compatibility with
  previous implementation. But, as I was at it, I made a number of
  minor improvements I am now going to describe.

2.1 Preserving blank lines 
===========================

   `org-move-item-up' and `org-move-item-down' will not eat blank
   lines anymore. You can move an item up and down and stay assured
   list will keep its integrity.

   The same is true for `org-sort-list' that would previously collapse
   the list being sorted. Sorting is now safe.

   `org-insert-item', when 'plain-list-item is set to 'auto in
   `org-blank-before-new-entry' (the default, I think), will work hard
   to guess the appropriate number of blank lines to insert before the
   item to come. The function is also much more predictable (in
   previous version, trying to insert an item with point on a blank
   line between 2 items would create a new headline).

2.2 Timer lists 
================

   There are three improvements in timer lists (C-c C-x -).

   1. When a new item is created, it should be properly indented and
      not sticked to column 0 anymore,

   2. When an item is inserted in a pre-existing timer list, it will
      take profit of what has been done to `org-insert-item',

   3. `org-sort-list' can now sort timer lists with the t and T
      commands.

   /Note/: in order to preserve lists integrity, Org Mode will send an
   error if you try to insert a timer list inside a list of another
   type.

2.3 Automatic rules 
====================

   I've added sets of rules (applied by default) that can improve
   lists experience. You can deactivate them individually by
   customizing `org-list-automatic-rules'.

   Bullet rule: Some may have noticed that you couldn't obtain *
                    as a bullet when cycling a list at column 0 or Org
                    would have taken them for headings.

                    I extended the idea. Now, * bullet will be changed
                    to - if you outdent it to column 0. This and the
                    fact that LaTeX exporter now recognizes such lists
                    as valid make *-lists very usable.

                    In the same register, cycling items of a
                    description list will not offer 1. or 1), as
                    ordered and description lists are incompatible.

   Checkbox rule: It replaces `org-provide-checkbox-statistics'
                      which has become obsolete.

   Indent rule: This set prevents user from breaking his list by
                    inadvertence, when indenting or outdenting items
                    and sub-trees. Only moves that keep list integrity
                    are allowed.

                    The main advantage of it is when you insert a new
                    item and immediately press one or more TAB,
                    positions offered will all be meaningful. Quick
                    and efficient.

                    As a special case, moving the top item of the list
                    will move the whole list with it.

   Insert rule: As a consequence of the new definition of lists,
                    items cannot be inserted inside a special block in
                    the middle of a list. With this rule activated,
                    item will be insert right before that special
                    block. If not, Org will only throw an error.

   Renumber rule: It replaces `org-auto-renumber-ordered-lists'
                      which has become obsolete.

   I think those rules make a sane default behavior (except for the
   indent rule, perhaps). And they are easy to disable if one think
   they get too much in the way.

2.4 `org-apply-on-list' 
========================

   It's not much, but I added that small function, inspired from
   `apply-of-rectangle', that might be of some use. It basically
   applies a function passed as argument to each item of the list
   (with a possible return value for functional usage).

   As an illustration, here is a small function that walks through a
   list (and its sublists, if any), checking every item with a blank
   checkbox whose body is matched by REGEXP. It returns the number of
   items checked.

  (defun my-check-o-matic (regexp)
    ;; Function we are going to apply.
    (let ((search-and-check 
           (lambda (count)
             (let* ((body-end (save-excursion (org-end-of-item-text-before-children)))
                    ;; Take care of any sublist first
                    (count (if (not (org-item-has-children-p))
                               count
                             (goto-char body-end)
                             (org-apply-on-list search-and-check count))))
               ;; Tests and checking if the formers are successful
               (if (and (save-excursion (re-search-forward regexp body-end t))
                        (org-at-item-checkbox-p)
                        (equal (match-string 1) "[ ]"))
                   (progn (org-toggle-checkbox) (1+ count))
                 count)))))
      ;; Call of `org-apply-on-list': notice initial value of counter
      (format "%d items checked"(org-apply-on-list search-and-check 0))))

3 Where can it be tried ? 
~~~~~~~~~~~~~~~~~~~~~~~~~~

  The source is at:

  git@github.com:ngz/org-mode-lists.git   branch: end-lists

  It is merged very frequently with git head, and I keep a clone of
  Org Mode master branch at the same place. So, you can switch from
  end-lists to master without too much hassle. It is very stable
  anyway, so you do not need to be an adventurous type.

  Feedback, suggestions and comments are welcome.

  Regards,

-- Nicolas

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