feat: support getting language icon by extension

## Details

Request: #233

When rendering an icon for a code block ideally we could handle both
the language name `python` as well as the extension `py`. Currently only
the former works while the latter results in a default icon from the
icon provider if configured.

To handle this resolve the input language to a filetype using
`vim.filetype.match` with a filename. The filename is generated by using
a random name, in this case `a`, and appending the language as the
extension. If the match is nil then assume the input language is the
filetype. For the python example this means:

- python: vim.filetype.match({ filename = 'a.python' }) -> nil or python -> python
- py: vim.filetype.match({ filename = 'a.py' }) -> python or py -> python

This approach is taken from the `nvim-treesitter` directive `set-lang-from-info-string`:
https://github.com/nvim-treesitter/nvim-treesitter/blob/master/lua/nvim-treesitter/query_predicates.lua,
aligning icon resolution with treesitter highlighting should make things
feel consistent. If syntax highlighting works we can probably get an
icon, if there is no syntax highlighting then we probably can't.

Other change, update troubleshooting docs to validate parse tree.

Author: MeanderingProgrammer

CHANGELOG.md

@@ -7,6 +7,7 @@
 - disabling background for code now keeps border [#220](https://github.com/MeanderingProgrammer/render-markdown.nvim/issues/220)
   [bee16b2](https://github.com/MeanderingProgrammer/render-markdown.nvim/commit/bee16b21bf47b64ceda8c9bb281d4b576d329c0f)
 - table support for all conceal levels [3da1bfc](https://github.com/MeanderingProgrammer/render-markdown.nvim/commit/3da1bfc4bd3a13fee57551f0b705ebcf2614d7a2)
+- roll own type validation to remove vim.validate [d69a885](https://github.com/MeanderingProgrammer/render-markdown.nvim/commit/d69a885e1bf21cb329d2eafe56fd80b6de627216)
 
 ### Bug Fixes
 

doc/troubleshooting.md

@@ -31,52 +31,85 @@ the `filetype` of the current buffer and make sure it is in that list:
 :lua vim.print(vim.bo.filetype)
 ```
 
-## Generating debug logs
+## Validate Parse Tree
 
-If all else fails hopefully the logs can provide some insight. This plugin
-ships with logging, however it only includes errors by default.
+Create a new `markdown` file locally with the following content:
 
-To help debug your issue you'll need to go through the following steps:
+```text
+# Heading
 
-1. Update the log level to `debug`
-2. Create a test file
-3. Generate logs from the test file
-4. Provide the logs in the issue
+- Item
 
-### Update the log level to `debug`
+> [!NOTE]
+> A note
 
-Change the plugin configuration to:
+- [x] Checked
+```
 
-```lua
-require('render-markdown').setup({
-    log_level = 'debug',
-})
+Run `:InspectTree` which should output the following:
+
+```text
+(document ; [0, 0] - [8, 0]
+  (section ; [0, 0] - [8, 0]
+    (atx_heading ; [0, 0] - [1, 0]
+      (atx_h1_marker) ; [0, 0] - [0, 1]
+      heading_content: (inline ; [0, 2] - [0, 9]
+        (inline))) ; [0, 2] - [0, 9]
+    (list ; [2, 0] - [4, 0]
+      (list_item ; [2, 0] - [4, 0]
+        (list_marker_minus) ; [2, 0] - [2, 2]
+        (paragraph ; [2, 2] - [3, 0]
+          (inline ; [2, 2] - [2, 6]
+            (inline)) ; [2, 2] - [2, 6]
+          (block_continuation)))) ; [3, 0] - [3, 0]
+    (block_quote ; [4, 0] - [6, 0]
+      (block_quote_marker) ; [4, 0] - [4, 2]
+      (paragraph ; [4, 2] - [6, 0]
+        (inline ; [4, 2] - [5, 8]
+          (inline ; [4, 2] - [5, 8]
+            (shortcut_link ; [4, 2] - [4, 9]
+              (link_text))) ; [4, 3] - [4, 8]
+          (block_continuation)))) ; [5, 0] - [5, 2]
+    (list ; [7, 0] - [8, 0]
+      (list_item ; [7, 0] - [8, 0]
+        (list_marker_minus) ; [7, 0] - [7, 2]
+        (task_list_marker_checked) ; [7, 2] - [7, 5]
+        (paragraph ; [7, 6] - [8, 0]
+          (inline ; [7, 6] - [7, 13]
+            (inline))))))) ; [7, 6] - [7, 13]
 ```
 
-### Create a test file
+If this is not what you see you likely need to update `nvim-treesitter` and your
+treesitter parsers.
 
-Create a new `markdown` file locally with the following content:
+## Generate Debug Logs
 
-```text
-# Heading
+If all else fails hopefully the logs can provide some insight. This plugin
+ships with logging, however it only includes errors by default.
 
-- Item
-  - Nested
+To help debug your issue you'll need to go through the following steps:
 
-> [!NOTE]
-> A note
+### 1) Create a Test File
 
-- [ ] Unchecked
-- [x] Checked
+Use the same file from [Validate Parse Tree](#validate-parse-tree).
+
+### 2) Update Log Level
+
+Change plugin configuration to output `debug` logs:
+
+```lua
+require('render-markdown').setup({
+    log_level = 'debug',
+})
 ```
 
-### Generate logs from the test file
+### 3) Generate Logs
 
-To do this restart Neovim and open the `markdown` file from the previous step.
+To do this restart Neovim and open the `markdown` file from the first step.
 
-This should trigger the render function by default, then close Neovim.
+This should trigger the rendering logic, then close Neovim.
 
-### Provide the logs in the issue
+### 4) Provide Logs in Issue
 
 Logs are written to a file typically located at: `~/.local/state/nvim/render-markdown.log`.
 

lua/render-markdown/health.lua

@@ -4,7 +4,7 @@ local state = require('render-markdown.state')
 local M = {}
 
 ---@private
-M.version = '7.5.4'
+M.version = '7.5.5'
 
 function M.check()
     M.start('version')

lua/render-markdown/lib/icons.lua

@@ -7,11 +7,14 @@ local M = {}
 ---@param language string
 ---@return string?, string?
 function M.get(language)
+    -- Handle input possibly being an extension rather than a language name
+    local file_type = vim.filetype.match({ filename = 'a.' .. language }) or language
+
     if has_mini_icons then
         ---@diagnostic disable-next-line: return-type-mismatch
-        return mini_icons.get('filetype', language)
+        return mini_icons.get('filetype', file_type)
     elseif has_devicons then
-        return devicons.get_icon_by_filetype(language)
+        return devicons.get_icon_by_filetype(file_type)
     else
         return nil, nil
     end

tests/code_spec.lua

@@ -42,7 +42,7 @@ describe('code.md', function()
 
         vim.list_extend(expected, {
             util.bullet(row:increment(2), 0, 1),
-            util.code_language(row:increment(2), 2, 'lua'),
+            util.code_language(row:increment(2), 2, 'py'),
         })
         for _ = 1, 2 do
             table.insert(expected, util.code_row(row:increment(), 2))
@@ -81,9 +81,9 @@ describe('code.md', function()
             '    8',
             '    9 ● Nested code',
             '   10',
-            '󰢱  11   󰢱 lua',
-            "   12   print('hello')",
-            "   13   print('world')",
+            '󰌠  11   󰌠 py',
+            '   12   print("hello")',
+            '   13   print("world")',
             '   14   ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀',
             '   15',
             '   16 ● Nested code with blank',
@@ -125,7 +125,7 @@ describe('code.md', function()
         local width_2 = 20
         vim.list_extend(expected, {
             util.bullet(row:increment(2), 0, 1),
-            util.code_language(row:increment(2), 2, 'lua', width_2),
+            util.code_language(row:increment(2), 2, 'py', width_2),
         })
         for _ = 1, 2 do
             vim.list_extend(expected, {
@@ -171,9 +171,9 @@ describe('code.md', function()
             '    8',
             '    9 ● Nested code',
             '   10',
-            '󰢱  11   󰢱 lua',
-            "   12     print('hello')",
-            "   13     print('world')",
+            '󰌠  11   󰌠 py',
+            '   12     print("hello")',
+            '   13     print("world")',
             '   14   ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀',
             '   15',
             '   16 ● Nested code with blank',

tests/data/code.md

@@ -8,9 +8,9 @@ fn main() {
 
 - Nested code
 
-  ```lua
-  print('hello')
-  print('world')
+  ```py
+  print("hello")
+  print("world")
   ```
 
 - Nested code with blank

tests/util.lua

@@ -225,17 +225,17 @@ end
 
 ---@param row integer
 ---@param col integer
----@param name 'python'|'lua'|'rust'
+---@param name 'python'|'py'|'rust'|'rs'|'lua'
 ---@param win_col? integer
 ---@return render.md.MarkInfo[]
 function M.code_language(row, col, name, win_col)
     local icon, highlight
-    if name == 'python' then
+    if name == 'python' or name == 'py' then
         icon, highlight = '󰌠 ', 'MiniIconsYellow'
+    elseif name == 'rust' or name == 'rs' then
+        icon, highlight = '󱘗 ', 'MiniIconsOrange'
     elseif name == 'lua' then
         icon, highlight = '󰢱 ', 'MiniIconsAzure'
-    elseif name == 'rust' then
-        icon, highlight = '󱘗 ', 'MiniIconsOrange'
     end
 
     ---@type render.md.MarkInfo