Add extension to support letter lists.

[joapuiib]

I think it would be nice to have an extension that supported all type of lists:

• Default (numbers).

• Upper case letters (type="A")

  A. List item
  B. List item
  C. List item
  

• Lower case letters (type="a")

  a. List item
  b. List item
  c. List item
  

• Upper case roman numbers (type="I")

  I. List item
  II. List item
  III. List item
  

• Lower case roman numbers (type="i")

  i. List item
  ii. List item
  iii. List item
  

Also, could be nice to be able to set the start number/letter, just as sane_lists does.

C. List item
D. List item

m. List item
n. List item

III. List item
IV. List item

ix. List item
x. List item

[facelessuser]

See issue #2418

[joapuiib]

Since it is something I'm planning to use, I have written a small extension with the previous use cases.

Just in case it is useful to someone, I'll leave it here: https://github.com/joapuiib/pymdown-fancylists

Thanks!

[facelessuser]

If I decide to support some iteration of this, it will be in pymdown-extensions, not some separate package. I'm simply in the prototype stage. I want to see what limitations there are, what potential issues could manifest, how fragile it is. All of this will feed into whether I choose to move forward with it. I'm also evaluating the various parts of the referenced "fancylist" in Pandoc. Do we monkey everything? Or do pick specific parts? Do we extend anything?

Anyway, I'm actively considering it, I just don't know what my decision is yet.

[facelessuser]

I think I will not be keeping (symbol) method if I move forward. I only had implemented (digit) in the prototype, and things like GitHub don't even support such syntax, they support symbol. and symbol). I don't want to complicate patterns to cover this case and my intention is not to provide a 1:1 implementation of Pandoc either.

Pandoc also adds a requirement for single letter uppercase list markers to have two spaces after the marker. I will likely add this requirement as well. I'm sure there are reasons.

[joapuiib]

Pandoc also adds a requirement for single letter uppercase list markers to have two spaces after the marker. I will likely add this requirement as well. I'm sure there are reasons.

As Pandoc documentation says:

The point of this rule is to ensure that normal paragraphs starting with people’s initials, like

B. Russell was an English philosopher.
do not get treated as list items.

This rule will not prevent

(C) 2007 Joe Smith
from being interpreted as a list item. In this case, a backslash escape can be used:

(C\) 2007 Joe Smith

[facelessuser]

This is what I'm thinking so far. By default, FancyList would extend list formats such that 1. and 1) would work. These formats would be added with functionality similar to Sane Lists but with the added behavior that swapping list types 1. vs 1) would force a new list.

All other formats are probably not supported syntactically in many editors. It's possible not everyone wants such behavior, and might actually control this automatically with CSS when lists are nested, but that's okay. I think additional list formats would be opt-in. You could enable one or all of them if you desire.

Someone using MkDocs might do this to enable all formats; decimal cannot be toggled and is always enabled.

markdown_extensions:
  - pymdownx.fancylists:
      addtional_ordered_styles:
      - alpha
      - roman
      - generic

[facelessuser]

Ugh, I meant to post this in the issue. If we can move conversation there it would be appreciated.