Feature request: lists with letters

[Titus von der Malsburg <malsburg@posteo.de>]

Items in lists can start with -, +, N), or N. (with N being an
integer).  It’s currently not possible, to use letters as in the
following examples:

a. First item
b. Second item

or

a) First item
b) Second item

I believe it would make sense to allow letters in org-mode because
that’s a very common way to label items in lists.  I know that this has
been discussed previously but to my knowledge there was no
resolution.  The counter argument against letters was that we wouldn’t
know what labels to use when there are more items than letters, but I
think this shouldn’t stop us.  Reasons:

a) Most lists have fewer items and cases where more than 26 labels are
   needed are rare.
b) If a list has more than 26 items, the user is free to switch to
   bullet points or numbers.
c) The limited number of letters hasn’t stopped people from using
   letters in many other contexts.  For example, LaTeX offers letters
   and people think it’s useful.
d) Similarly, people often use Roman numerals (e.g., iv.) although
   they also quickly become impractical (999 = CMXCIX).
e) In some (academic) contexts, e.g. in linguistics, letters are
   conventionally used to label items in lists.
f) Letters worked perfectly fine in this list.

As to the question what org mode should do if a list is two long for
letters: Here are two possible solutions:

a) Label all items beyond the 26th with z, to make it visually very
   salient that there are not enough letters.
b) Start over from letter a after z.
c) Count in base 26 using letters as digits: a … z aa … az ba … bz …

Personally, I would prefer solution c because it gives each item a
unique label to which we can refer.  But solutions a and b would be ok,
too.  It doesn’t really matter because this is just an uninteresting
edge case and we shouldn’t obsess about it when the default case (<=26
items) is complete unproblematic.

Thanks for considering this proposal.

  Titus