feat: add default icons for ordered lists

## Details

Request: #250

Previously we supported adding icons for ordered lists in much the same
way as unordered, however by default the value was empty.

To do an auto ordering for the pattern of using `1.` for every value we
now provide a default value. However, because ordered lists can go on
and we want to support arbitrary lengths we now also support setting a
function for both ordered and unordered list icons. The function is
called with both the level of the list and the index of the item and
whatever value is returned is used as the icon.

The default function just concatenates a period after the index value
and ignores the level.

Author: MeanderingProgrammer

README.md

@@ -362,14 +362,20 @@ require('render-markdown').setup({
         -- Turn on / off list bullet rendering
         enabled = true,
         -- Replaces '-'|'+'|'*' of 'list_item'
-        -- How deeply nested the list is determines the 'level' which is used to index into the list using a cycle
-        -- The item number in the list is used to index into the value using a clamp if the value is also a list
+        -- How deeply nested the list is determines the 'level', how far down at that level determines the 'index'
+        -- If a function is provided both of these values are passed in using 1 based indexing
+        -- If a list is provided we index into it using a cycle based on the level
+        -- If the value at that level is also a list we further index into it using a clamp based on the index
         -- If the item is a 'checkbox' a conceal is used to hide the bullet instead
         icons = { '●', '○', '◆', '◇' },
         -- Replaces 'n.'|'n)' of 'list_item'
-        -- How deeply nested the list is determines the 'level' which is used to index into the list using a cycle
-        -- The item number in the list is used to index into the value using a clamp if the value is also a list
-        ordered_icons = {},
+        -- How deeply nested the list is determines the 'level', how far down at that level determines the 'index'
+        -- If a function is provided both of these values are passed in using 1 based indexing
+        -- If a list is provided we index into it using a cycle based on the level
+        -- If the value at that level is also a list we further index into it using a clamp based on the index
+        ordered_icons = function(level, index)
+            return string.format('%d.', index)
+        end,
         -- Padding to add to the left of bullet point
         left_pad = 0,
         -- Padding to add to the right of bullet point
@@ -859,14 +865,20 @@ require('render-markdown').setup({
         -- Turn on / off list bullet rendering
         enabled = true,
         -- Replaces '-'|'+'|'*' of 'list_item'
-        -- How deeply nested the list is determines the 'level' which is used to index into the list using a cycle
-        -- The item number in the list is used to index into the value using a clamp if the value is also a list
+        -- How deeply nested the list is determines the 'level', how far down at that level determines the 'index'
+        -- If a function is provided both of these values are passed in using 1 based indexing
+        -- If a list is provided we index into it using a cycle based on the level
+        -- If the value at that level is also a list we further index into it using a clamp based on the index
         -- If the item is a 'checkbox' a conceal is used to hide the bullet instead
         icons = { '●', '○', '◆', '◇' },
         -- Replaces 'n.'|'n)' of 'list_item'
-        -- How deeply nested the list is determines the 'level' which is used to index into the list using a cycle
-        -- The item number in the list is used to index into the value using a clamp if the value is also a list
-        ordered_icons = {},
+        -- How deeply nested the list is determines the 'level', how far down at that level determines the 'index'
+        -- If a function is provided both of these values are passed in using 1 based indexing
+        -- If a list is provided we index into it using a cycle based on the level
+        -- If the value at that level is also a list we further index into it using a clamp based on the index
+        ordered_icons = function(level, index)
+            return string.format('%d.', index)
+        end,
         -- Padding to add to the left of bullet point
         left_pad = 0,
         -- Padding to add to the right of bullet point

doc/render-markdown.txt

@@ -1,4 +1,4 @@
-*render-markdown.txt*         For 0.10.0         Last change: 2024 December 04
+*render-markdown.txt*         For 0.10.0         Last change: 2024 December 05
 
 ==============================================================================
 Table of Contents                          *render-markdown-table-of-contents*
@@ -409,14 +409,20 @@ Default Configuration ~
             -- Turn on / off list bullet rendering
             enabled = true,
             -- Replaces '-'|'+'|'*' of 'list_item'
-            -- How deeply nested the list is determines the 'level' which is used to index into the list using a cycle
-            -- The item number in the list is used to index into the value using a clamp if the value is also a list
+            -- How deeply nested the list is determines the 'level', how far down at that level determines the 'index'
+            -- If a function is provided both of these values are passed in using 1 based indexing
+            -- If a list is provided we index into it using a cycle based on the level
+            -- If the value at that level is also a list we further index into it using a clamp based on the index
             -- If the item is a 'checkbox' a conceal is used to hide the bullet instead
             icons = { '●', '○', '◆', '◇' },
             -- Replaces 'n.'|'n)' of 'list_item'
-            -- How deeply nested the list is determines the 'level' which is used to index into the list using a cycle
-            -- The item number in the list is used to index into the value using a clamp if the value is also a list
-            ordered_icons = {},
+            -- How deeply nested the list is determines the 'level', how far down at that level determines the 'index'
+            -- If a function is provided both of these values are passed in using 1 based indexing
+            -- If a list is provided we index into it using a cycle based on the level
+            -- If the value at that level is also a list we further index into it using a clamp based on the index
+            ordered_icons = function(level, index)
+                return string.format('%d.', index)
+            end,
             -- Padding to add to the left of bullet point
             left_pad = 0,
             -- Padding to add to the right of bullet point
@@ -896,14 +902,20 @@ Bullet Point Configuration ~
             -- Turn on / off list bullet rendering
             enabled = true,
             -- Replaces '-'|'+'|'*' of 'list_item'
-            -- How deeply nested the list is determines the 'level' which is used to index into the list using a cycle
-            -- The item number in the list is used to index into the value using a clamp if the value is also a list
+            -- How deeply nested the list is determines the 'level', how far down at that level determines the 'index'
+            -- If a function is provided both of these values are passed in using 1 based indexing
+            -- If a list is provided we index into it using a cycle based on the level
+            -- If the value at that level is also a list we further index into it using a clamp based on the index
             -- If the item is a 'checkbox' a conceal is used to hide the bullet instead
             icons = { '●', '○', '◆', '◇' },
             -- Replaces 'n.'|'n)' of 'list_item'
-            -- How deeply nested the list is determines the 'level' which is used to index into the list using a cycle
-            -- The item number in the list is used to index into the value using a clamp if the value is also a list
-            ordered_icons = {},
+            -- How deeply nested the list is determines the 'level', how far down at that level determines the 'index'
+            -- If a function is provided both of these values are passed in using 1 based indexing
+            -- If a list is provided we index into it using a cycle based on the level
+            -- If the value at that level is also a list we further index into it using a clamp based on the index
+            ordered_icons = function(level, index)
+                return string.format('%d.', index)
+            end,
             -- Padding to add to the left of bullet point
             left_pad = 0,
             -- Padding to add to the right of bullet point

lua/render-markdown/health.lua

@@ -4,7 +4,7 @@ local state = require('render-markdown.state')
 local M = {}
 
 ---@private
-M.version = '7.6.10'
+M.version = '7.6.11'
 
 function M.check()
     M.start('version')

lua/render-markdown/init.lua

@@ -127,10 +127,12 @@ local M = {}
 ---@field public checked? render.md.UserCheckboxComponent
 ---@field public custom? table<string, render.md.UserCustomCheckbox>
 
+---@alias render.md.bullet.Icons string[]|string[][]|fun(level: integer, index: integer): string?
+
 ---@class (exact) render.md.UserBullet
 ---@field public enabled? boolean
----@field public icons? (string|string[])[]
----@field public ordered_icons? (string|string[])[]
+---@field public icons? render.md.bullet.Icons
+---@field public ordered_icons? render.md.bullet.Icons
 ---@field public left_pad? integer
 ---@field public right_pad? integer
 ---@field public highlight? string
@@ -494,14 +496,20 @@ M.default_config = {
         -- Turn on / off list bullet rendering
         enabled = true,
         -- Replaces '-'|'+'|'*' of 'list_item'
-        -- How deeply nested the list is determines the 'level' which is used to index into the list using a cycle
-        -- The item number in the list is used to index into the value using a clamp if the value is also a list
+        -- How deeply nested the list is determines the 'level', how far down at that level determines the 'index'
+        -- If a function is provided both of these values are passed in using 1 based indexing
+        -- If a list is provided we index into it using a cycle based on the level
+        -- If the value at that level is also a list we further index into it using a clamp based on the index
         -- If the item is a 'checkbox' a conceal is used to hide the bullet instead
         icons = { '●', '○', '◆', '◇' },
         -- Replaces 'n.'|'n)' of 'list_item'
-        -- How deeply nested the list is determines the 'level' which is used to index into the list using a cycle
-        -- The item number in the list is used to index into the value using a clamp if the value is also a list
-        ordered_icons = {},
+        -- How deeply nested the list is determines the 'level', how far down at that level determines the 'index'
+        -- If a function is provided both of these values are passed in using 1 based indexing
+        -- If a list is provided we index into it using a cycle based on the level
+        -- If the value at that level is also a list we further index into it using a clamp based on the index
+        ordered_icons = function(level, index)
+            return string.format('%d.', index)
+        end,
         -- Padding to add to the left of bullet point
         left_pad = 0,
         -- Padding to add to the right of bullet point

lua/render-markdown/render/list_item.lua

@@ -87,10 +87,16 @@ end
 ---@private
 ---@param level integer
 function Render:icon(level)
+    local index = self.node:sibling_count('list_item')
     local icons = self.data.ordered and self.bullet.ordered_icons or self.bullet.icons
-    local icon = List.cycle(icons, level)
-    if type(icon) == 'table' then
-        icon = List.clamp(icon, self.node:sibling_count('list_item'))
+    local icon = nil
+    if type(icons) == 'function' then
+        icon = icons(level, index)
+    else
+        icon = List.cycle(icons, level)
+        if type(icon) == 'table' then
+            icon = List.clamp(icon, index)
+        end
     end
     if icon == nil then
         return

lua/render-markdown/state.lua

@@ -189,7 +189,7 @@ function M.validate()
                     :type('enabled', 'boolean')
                     :type({ 'left_pad', 'right_pad' }, 'number')
                     :type('highlight', 'string')
-                    :list_or_list_of_list({ 'icons', 'ordered_icons' }, 'string')
+                    :list_or_list_of_list({ 'icons', 'ordered_icons' }, 'string', 'function')
                     :check()
             end)
             :nested('checkbox', function(checkbox)

lua/render-markdown/types.lua

@@ -110,8 +110,8 @@
 
 ---@class (exact) render.md.Bullet
 ---@field public enabled boolean
----@field public icons (string|string[])[]
----@field public ordered_icons (string|string[])[]
+---@field public icons render.md.bullet.Icons
+---@field public ordered_icons render.md.bullet.Icons
 ---@field public left_pad integer
 ---@field public right_pad integer
 ---@field public highlight string

tests/list_table_spec.lua

@@ -26,7 +26,12 @@ describe('list_table.md', function()
 
         vim.list_extend(expected, util.heading(row:increment(2), 1))
 
-        vim.list_extend(expected, util.heading(row:increment(5), 1))
+        vim.list_extend(expected, {
+            util.ordered(row:increment(2), 0, '1.'),
+            util.ordered(row:increment(1), 0, '2.'),
+        })
+
+        vim.list_extend(expected, util.heading(row:increment(2), 1))
 
         vim.list_extend(expected, {
             util.table_border(row:increment(2), true, { 8, 15, 7, 6 }),

tests/util.lua

@@ -165,6 +165,20 @@ function M.bullet(row, col, level, spaces)
     }
 end
 
+---@param row integer
+---@param col integer
+---@param text string
+---@return render.md.MarkInfo
+function M.ordered(row, col, text)
+    ---@type render.md.MarkInfo
+    return {
+        row = { row, row },
+        col = { col, col + 3 },
+        virt_text = { { text, M.hl('Bullet') } },
+        virt_text_pos = 'overlay',
+    }
+end
+
 ---@param row integer
 ---@param start_col integer
 ---@param end_col integer