feat: allow nested markdown to be skipped

## Details

Request: #510

Users would like the ability skip rendering `markdown` code blocks
inside of `markdown` files. This is in order to make it appear more
distinct from the overall context of the markdown file, to some extent
treating it more like code than a document.

For now I've made disabling the nested rendering opt-in, via the top
level `nested` option which has a default value of `true`. To disable
nested rendering:

```lua
require('render-markdown').setup({
    nested = false,
})
```

I initially thought this feature would be more complex to implement due
to how we traverse the individual `markdown` trees, however using the
`LanguageTree:parent()` API we can count the number of `markdown` trees
on our path to the root node skip nodes that are `> 1` level deep.

Note: opting in to the feature has a small performance penalty as we
must check whether trees are nested for each individual tree, which for
`markdown` includes all the `inline` nodes.

Author: MeanderingProgrammer

CHANGELOG.md

@@ -10,6 +10,8 @@
   [146d4ff](https://github.com/MeanderingProgrammer/render-markdown.nvim/commit/146d4ff582017f1a1a16ada841aa08175a87aaea)
 - add scope_highlight to wiki config [ca86b59](https://github.com/MeanderingProgrammer/render-markdown.nvim/commit/ca86b5941a56b04ac140837ee7a366cf3fa5cd88)
 - add cell_offset function to pipe_table configuration [e5c3c50](https://github.com/MeanderingProgrammer/render-markdown.nvim/commit/e5c3c500d66e9aaf04c116cdfdb0b040d56a1521)
+- inline render single line latex equations [#508](https://github.com/MeanderingProgrammer/render-markdown.nvim/issues/508)
+  [b7dad79](https://github.com/MeanderingProgrammer/render-markdown.nvim/commit/b7dad793f4750b7e95884c0db374b917898a979b)
 
 ### Bug Fixes
 

README.md

@@ -209,10 +209,13 @@ require('render-markdown').setup({
     log_runtime = false,
     -- Filetypes this plugin will run on.
     file_types = { 'markdown' },
-    -- Takes buffer as input, if it returns true this plugin will not attach to the buffer
+    -- Takes buffer as input, if it returns true this plugin will not attach to the buffer.
     ignore = function()
         return false
     end,
+    -- Whether markdown should be rendered when nested inside markdown, i.e. markdown code block
+    -- inside markdown file.
+    nested = true,
     -- Additional events that will trigger this plugin's render loop.
     change_events = {},
     -- Whether the treesitter highlighter should be restarted after this plugin attaches to its

doc/render-markdown.txt

@@ -1,4 +1,4 @@
-*render-markdown.txt*       For NVIM v0.11.3       Last change: 2025 August 25
+*render-markdown.txt*       For NVIM v0.11.3       Last change: 2025 August 29
 
 ==============================================================================
 Table of Contents                          *render-markdown-table-of-contents*
@@ -275,10 +275,13 @@ Default Configuration ~
         log_runtime = false,
         -- Filetypes this plugin will run on.
         file_types = { 'markdown' },
-        -- Takes buffer as input, if it returns true this plugin will not attach to the buffer
+        -- Takes buffer as input, if it returns true this plugin will not attach to the buffer.
         ignore = function()
             return false
         end,
+        -- Whether markdown should be rendered when nested inside markdown, i.e. markdown code block
+        -- inside markdown file.
+        nested = true,
         -- Additional events that will trigger this plugin's render loop.
         change_events = {},
         -- Whether the treesitter highlighter should be restarted after this plugin attaches to its

lua/render-markdown/core/handlers.lua

@@ -1,6 +1,7 @@
 local log = require('render-markdown.core.log')
 
 ---@class render.md.handlers.Config
+---@field nested boolean
 ---@field custom table<string, render.md.Handler>
 
 ---@class render.md.Handlers
@@ -31,13 +32,15 @@ function M.run(context, parser)
     -- parse markdown after other nodes to get accurate state
     local markdown = {} ---@type render.md.handler.Context[]
     parser:for_each_tree(function(tree, language_tree)
-        ---@type render.md.handler.Context
-        local ctx = { buf = context.buf, root = tree:root() }
-        local language = language_tree:lang()
-        if language == 'markdown' then
-            markdown[#markdown + 1] = ctx
-        else
-            vim.list_extend(marks, M.tree(context, ctx, language))
+        if M.config.nested or M.level(language_tree) == 1 then
+            ---@type render.md.handler.Context
+            local ctx = { buf = context.buf, root = tree:root() }
+            local language = language_tree:lang()
+            if language == 'markdown' then
+                markdown[#markdown + 1] = ctx
+            else
+                vim.list_extend(marks, M.tree(context, ctx, language))
+            end
         end
     end)
     for _, ctx in ipairs(markdown) do
@@ -46,6 +49,20 @@ function M.run(context, parser)
     return marks
 end
 
+---@private
+---@param tree? vim.treesitter.LanguageTree
+---@return integer
+function M.level(tree)
+    local result = 0
+    while tree do
+        if tree:lang() == 'markdown' then
+            result = result + 1
+        end
+        tree = tree:parent()
+    end
+    return result
+end
+
 ---Run custom & builtin handlers when available. Custom handler is always
 ---executed, builtin handler is skipped if custom does not specify extends.
 ---@private

lua/render-markdown/health.lua

@@ -5,7 +5,7 @@ local state = require('render-markdown.state')
 local M = {}
 
 ---@private
-M.version = '8.7.14'
+M.version = '8.7.15'
 
 function M.check()
     M.start('versions')

lua/render-markdown/init.lua

@@ -7,6 +7,7 @@ local M = {}
 ---@field log_runtime boolean
 ---@field file_types string[]
 ---@field ignore fun(buf: integer): boolean
+---@field nested boolean
 ---@field change_events string[]
 ---@field restart_highlighter boolean
 ---@field injections render.md.injection.Configs
@@ -72,10 +73,13 @@ M.default = {
     log_runtime = false,
     -- Filetypes this plugin will run on.
     file_types = { 'markdown' },
-    -- Takes buffer as input, if it returns true this plugin will not attach to the buffer
+    -- Takes buffer as input, if it returns true this plugin will not attach to the buffer.
     ignore = function()
         return false
     end,
+    -- Whether markdown should be rendered when nested inside markdown, i.e. markdown code block
+    -- inside markdown file.
+    nested = true,
     -- Additional events that will trigger this plugin's render loop.
     change_events = {},
     -- Whether the treesitter highlighter should be restarted after this plugin attaches to its

lua/render-markdown/state.lua

@@ -16,6 +16,7 @@ function M.setup(config)
     M.config = config
     M.enabled = config.enabled
     require('render-markdown.core.handlers').setup({
+        nested = config.nested,
         custom = config.custom_handlers,
     })
     require('render-markdown.core.log').setup({
@@ -90,6 +91,7 @@ function M.validate()
             log_runtime = { type = 'boolean' },
             file_types = { list = { type = 'string' } },
             ignore = { type = 'function' },
+            nested = { type = 'boolean' },
             change_events = { list = { type = 'string' } },
             restart_highlighter = { type = 'boolean' },
             injections = require('render-markdown.config.injections').schema(),

lua/render-markdown/types.lua

@@ -6,6 +6,7 @@
 ---@field log_runtime? boolean
 ---@field file_types? string[]
 ---@field ignore? fun(buf: integer): boolean
+---@field nested? boolean
 ---@field change_events? string[]
 ---@field restart_highlighter? boolean
 ---@field injections? render.md.injection.UserConfigs