[Doc-SIG] reST ordered list syntax extension

[Andrew Harrington]

Desired feature change in restructured text (reST) ordered lists:

Being able to add ordered list entries to the middle of a list without 
renumbering would be very useful. 

If I start with:


1.  first
2.  second

  a. sub a

     para

  b. sub b

3.  third

And I want to insert entry NEW after 1, I must renumber:

1.  first
2.  NEW
3.  second

  a. sub a

     para

  b. sub b

4. third

I suggest that the first entry in a list start with the actual format 
desired, but for later entries allow '#':

1.  first
#.  second

  a. sub a

     para

  #. sub b

#.  third


which would make the insertion easy:

1.  first
#.  NEW
#.  second

  a. sub a

     para

  #. sub b

#.  third

The parser already keeps track of what the next sequence identifier would 
be and issues errors if they are wrong.  Why not just allow the # with the 
same punctuation after it and indentation before as in the first entry, 
and rather than declaring an error, substitute in the next in the 
sequence?

An extension could allow fully labeled sublist entries  If you wanted:

1.  first
2.  second

      2.a. sub a

           para

      2.b. sub b

3. third

you could use in the extended reST:

1.  first
#.  second

  #.a. sub a

       para

  #.#. sub b

#. third

The assumption is that if a first sub entry starts with one or more '#' 
and punctuation (the '#.' here), they are assumed to be repeats of the 
current outer levels, and there must be an explicit subsequence starter in 
addition (the 'a' here).  I have written in that further sub entries must 
have the same prefix ('#.' here) as the first subentry.  A more concise 
alternative would be to _assume the same prefix, and just allow 

   #.#. sub b

to be

     #. sub b

I am not sure if the latter alternative should be indented to match the 
first instead of the second '#' in the alternate version above.

The punctuation is important to be included explicitly if desired.  
If I gave input

   #a. sub a

I would get out the more concise output

   2a. sub a

Comments?

Thanks
Andy Harrington