feat: support math superscript characters and body transformer for footnotes

## Details

Adds some missing standard superscript characters for +, -, =.

Also adds a `body` option to footnotes that allows the user to modify
the text however they want before adding prefix / suffix and converting
to superscript. User can define this and disable the superscript to
completely control the rendering. Default implementation simply returns
the input text without any modifications.

Author: MeanderingProgrammer

CHANGELOG.md

@@ -7,6 +7,10 @@
 - link.highlight_title option [#583](https://github.com/MeanderingProgrammer/render-markdown.nvim/issues/583)
   [ae89236](https://github.com/MeanderingProgrammer/render-markdown.nvim/commit/ae89236e2389836cf1c3787b2b80d5d8685cc13f)
 - toggle WikiLink rendering via enabled flag [8314d14](https://github.com/MeanderingProgrammer/render-markdown.nvim/commit/8314d14b9f56306bc876fb3b386f31dc8c5a2711)
+- center code language position [#591](https://github.com/MeanderingProgrammer/render-markdown.nvim/issues/591)
+  [99bfa5d](https://github.com/MeanderingProgrammer/render-markdown.nvim/commit/99bfa5d61381a29eedc75810898cb9c0fc755064)
+- add priority to sign configuration [#601](https://github.com/MeanderingProgrammer/render-markdown.nvim/issues/601)
+  [996ec12](https://github.com/MeanderingProgrammer/render-markdown.nvim/commit/996ec12e1164e56401babf236c56cb2d9321d923)
 
 ## 8.11.0 (2026-01-07)
 

README.md

@@ -784,6 +784,11 @@ require('render-markdown').setup({
             enabled = true,
             -- Inlined with content.
             icon = '󰯔 ',
+            -- Custom processing for footnote body to show.
+            -- Runs before prefix / suffix are added and superscript processing.
+            body = function(ctx)
+                return ctx.text
+            end,
             -- Replace value with superscript equivalent.
             superscript = true,
             -- Added before link content.
@@ -1566,6 +1571,11 @@ require('render-markdown').setup({
             enabled = true,
             -- Inlined with content.
             icon = '󰯔 ',
+            -- Custom processing for footnote body to show.
+            -- Runs before prefix / suffix are added and superscript processing.
+            body = function(ctx)
+                return ctx.text
+            end,
             -- Replace value with superscript equivalent.
             superscript = true,
             -- Added before link content.

doc/render-markdown.txt

@@ -850,6 +850,11 @@ Default Configuration ~
                 enabled = true,
                 -- Inlined with content.
                 icon = '󰯔 ',
+                -- Custom processing for footnote body to show.
+                -- Runs before prefix / suffix are added and superscript processing.
+                body = function(ctx)
+                    return ctx.text
+                end,
                 -- Replace value with superscript equivalent.
                 superscript = true,
                 -- Added before link content.
@@ -1612,6 +1617,11 @@ Link Configuration ~
                 enabled = true,
                 -- Inlined with content.
                 icon = '󰯔 ',
+                -- Custom processing for footnote body to show.
+                -- Runs before prefix / suffix are added and superscript processing.
+                body = function(ctx)
+                    return ctx.text
+                end,
                 -- Replace value with superscript equivalent.
                 superscript = true,
                 -- Added before link content.

lua/render-markdown/health.lua

@@ -6,7 +6,7 @@ local state = require('render-markdown.state')
 local M = {}
 
 ---@private
-M.version = '8.11.4'
+M.version = '8.11.5'
 
 function M.check()
     M.start('versions')

lua/render-markdown/lib/converter.lua

@@ -5,6 +5,7 @@ local M = {}
 ---@private
 M.superscripts = {
     [' '] = ' ', ['('] = '⁽', [')'] = '⁾',
+    ['+'] = '⁺', ['-'] = '⁻', ['='] = '⁼',
 
     ['0'] = '⁰', ['1'] = '¹', ['2'] = '²', ['3'] = '³', ['4'] = '⁴',
     ['5'] = '⁵', ['6'] = '⁶', ['7'] = '⁷', ['8'] = '⁸', ['9'] = '⁹',

lua/render-markdown/render/inline/shortcut.lua

@@ -51,7 +51,8 @@ function Render:footnote(text)
     if not config.enabled then
         return
     end
-    local body = config.prefix .. text .. config.suffix ---@type string?
+    local body = config.body({ text = text })
+    body = body and config.prefix .. body .. config.suffix
     if config.superscript then
         body = body and converter.superscript(body)
     end

lua/render-markdown/settings.lua

@@ -1228,25 +1228,29 @@ M.link = {}
 ---@field wiki render.md.link.wiki.Config
 ---@field custom table<string, render.md.link.custom.Config>
 
----@class (exact) render.md.link.Context
----@field buf integer
----@field row integer
----@field start_col integer
----@field end_col integer
----@field destination string
----@field alias? string
+---@class (exact) render.md.link.footnote.Context
+---@field text string
 
 ---@class (exact) render.md.link.footnote.Config
 ---@field enabled boolean
 ---@field icon string
+---@field body fun(ctx: render.md.link.footnote.Context): string?
 ---@field superscript boolean
 ---@field prefix string
 ---@field suffix string
 
+---@class (exact) render.md.link.wiki.Context
+---@field buf integer
+---@field row integer
+---@field start_col integer
+---@field end_col integer
+---@field destination string
+---@field alias? string
+
 ---@class (exact) render.md.link.wiki.Config
 ---@field enabled boolean
 ---@field icon string
----@field body fun(ctx: render.md.link.Context): render.md.mark.Text|string?
+---@field body fun(ctx: render.md.link.wiki.Context): render.md.mark.Text|string?
 ---@field highlight string
 ---@field scope_highlight? string
 
@@ -1275,6 +1279,11 @@ M.link.default = {
         enabled = true,
         -- Inlined with content.
         icon = '󰯔 ',
+        -- Custom processing for footnote body to show.
+        -- Runs before prefix / suffix are added and superscript processing.
+        body = function(ctx)
+            return ctx.text
+        end,
         -- Replace value with superscript equivalent.
         superscript = true,
         -- Added before link content.
@@ -1353,6 +1362,7 @@ function M.link.schema()
             record = {
                 enabled = { type = 'boolean' },
                 icon = { type = 'string' },
+                body = { type = 'function' },
                 superscript = { type = 'boolean' },
                 prefix = { type = 'string' },
                 suffix = { type = 'string' },

lua/render-markdown/types.lua

@@ -223,14 +223,15 @@
 ---@class (exact) render.md.link.footnote.UserConfig
 ---@field enabled? boolean
 ---@field icon? string
+---@field body? fun(ctx: render.md.link.footnote.Context): string?
 ---@field superscript? boolean
 ---@field prefix? string
 ---@field suffix? string
 
 ---@class (exact) render.md.link.wiki.UserConfig
 ---@field enabled? boolean
 ---@field icon? string
----@field body? fun(ctx: render.md.link.Context): render.md.mark.Text|string?
+---@field body? fun(ctx: render.md.link.wiki.Context): render.md.mark.Text|string?
 ---@field highlight? string
 ---@field scope_highlight? string