feat: Check highlight enabled per language in healthcheck

## Details

Rather than checking if the highlight module is enabled for
treesitter check that each language is individually enabled.

This should hanlde cases like this:
#89

Minor refactor, standardize on `function M.method` instead of
`M.method = function`. Used both in a few places, better to
stick to one.

Author: MeanderingProgrammer

Diff for: doc/render-markdown.txt

@@ -1,4 +1,4 @@
-*render-markdown.txt*           For 0.10.0           Last change: 2024 July 24
+*render-markdown.txt*           For 0.10.0           Last change: 2024 July 25
 
 ==============================================================================
 Table of Contents                          *render-markdown-table-of-contents*

Diff for: lua/render-markdown/colors.lua

@@ -64,15 +64,17 @@ end
 ---@param foreground string
 ---@param background string
 ---@return string
-M.combine = function(foreground, background)
+function M.combine(foreground, background)
     local name = string.format('%s_%s_%s', M.prefix, foreground, background)
     if not vim.tbl_contains(cache.highlights, name) then
         local fg = M.get_hl(foreground)
         local bg = M.get_hl(background)
         vim.api.nvim_set_hl(0, name, {
             fg = fg.fg,
             bg = bg.bg,
+            ---@diagnostic disable-next-line: undefined-field
             ctermfg = fg.ctermfg,
+            ---@diagnostic disable-next-line: undefined-field
             ctermbg = bg.ctermbg,
         })
         table.insert(cache.highlights, name)
@@ -82,14 +84,16 @@ end
 
 ---@param highlight string
 ---@return string
-M.inverse = function(highlight)
+function M.inverse(highlight)
     local name = string.format('%s_Inverse_%s', M.prefix, highlight)
     if not vim.tbl_contains(cache.highlights, name) then
         local hl = M.get_hl(highlight)
         vim.api.nvim_set_hl(0, name, {
             fg = hl.bg,
             bg = hl.fg,
+            ---@diagnostic disable-next-line: undefined-field
             ctermbg = hl.ctermfg,
+            ---@diagnostic disable-next-line: undefined-field
             ctermfg = hl.ctermbg,
         })
         table.insert(cache.highlights, name)
@@ -100,7 +104,7 @@ end
 ---@private
 ---@param name string
 ---@return vim.api.keyset.hl_info
-M.get_hl = function(name)
+function M.get_hl(name)
     return vim.api.nvim_get_hl(0, { name = name, link = false })
 end
 

Diff for: lua/render-markdown/component.lua

@@ -10,7 +10,7 @@ local M = {}
 ---@param text string
 ---@param comparison 'exact'|'contains'
 ---@return render.md.Component?
-M.callout = function(text, comparison)
+function M.callout(text, comparison)
     ---@param callout render.md.CustomComponent
     ---@return boolean
     local function matches(callout)
@@ -33,7 +33,7 @@ end
 ---@param text string
 ---@param comparison 'exact'|'starts'
 ---@return render.md.Component?
-M.checkbox = function(text, comparison)
+function M.checkbox(text, comparison)
     ---@param checkbox render.md.CustomComponent
     ---@return boolean
     local function matches(checkbox)

Diff for: lua/render-markdown/handler/latex.lua

@@ -16,7 +16,7 @@ local M = {}
 ---@param root TSNode
 ---@param buf integer
 ---@return render.md.Mark[]
-M.parse = function(root, buf)
+function M.parse(root, buf)
     local latex = state.config.latex
     if not latex.enabled then
         return {}

Diff for: lua/render-markdown/handler/markdown.lua

@@ -15,7 +15,7 @@ local M = {}
 ---@param root TSNode
 ---@param buf integer
 ---@return render.md.Mark[]
-M.parse = function(root, buf)
+function M.parse(root, buf)
     local marks = {}
     local query = state.markdown_query
     for id, node in query:iter_captures(root, buf) do
@@ -59,7 +59,7 @@ end
 ---@param buf integer
 ---@param info render.md.NodeInfo
 ---@return render.md.Mark[]
-M.render_heading = function(buf, info)
+function M.render_heading(buf, info)
     local heading = state.config.heading
     if not heading.enabled then
         return {}
@@ -134,7 +134,7 @@ end
 ---@param buf integer
 ---@param info render.md.NodeInfo
 ---@return render.md.Mark?
-M.render_dash = function(buf, info)
+function M.render_dash(buf, info)
     local dash = state.config.dash
     if not dash.enabled then
         return nil
@@ -164,7 +164,7 @@ end
 ---@param buf integer
 ---@param info render.md.NodeInfo
 ---@return render.md.Mark[]
-M.render_code = function(buf, info)
+function M.render_code(buf, info)
     local code = state.config.code
     if not code.enabled or code.style == 'none' then
         return {}
@@ -289,7 +289,7 @@ end
 ---@param info render.md.NodeInfo
 ---@param code_block render.md.NodeInfo
 ---@return render.md.Mark[]
-M.render_language = function(buf, info, code_block)
+function M.render_language(buf, info, code_block)
     local code = state.config.code
     if not vim.tbl_contains({ 'language', 'full' }, code.style) then
         return {}
@@ -336,7 +336,7 @@ end
 ---@param buf integer
 ---@param info render.md.NodeInfo
 ---@return render.md.Mark[]
-M.render_list_marker = function(buf, info)
+function M.render_list_marker(buf, info)
     ---@return boolean
     local function sibling_checkbox()
         if not state.config.checkbox.enabled then
@@ -418,7 +418,7 @@ end
 ---@param info render.md.NodeInfo
 ---@param checkbox_state render.md.CheckboxComponent
 ---@return render.md.Mark?
-M.render_checkbox = function(info, checkbox_state)
+function M.render_checkbox(info, checkbox_state)
     local checkbox = state.config.checkbox
     if not checkbox.enabled then
         return nil
@@ -441,7 +441,7 @@ end
 ---@param info render.md.NodeInfo
 ---@param block_quote render.md.NodeInfo
 ---@return render.md.Mark?
-M.render_quote_marker = function(info, block_quote)
+function M.render_quote_marker(info, block_quote)
     local quote = state.config.quote
     if not quote.enabled then
         return nil
@@ -471,7 +471,7 @@ end
 ---@param text string?
 ---@param highlight string
 ---@return render.md.Mark?
-M.render_sign = function(buf, info, text, highlight)
+function M.render_sign(buf, info, text, highlight)
     local sign = state.config.sign
     if not sign.enabled or text == nil then
         return nil
@@ -497,7 +497,7 @@ end
 ---@param buf integer
 ---@param info render.md.NodeInfo
 ---@return render.md.Mark[]
-M.render_table = function(buf, info)
+function M.render_table(buf, info)
     local pipe_table = state.config.pipe_table
     if not pipe_table.enabled or pipe_table.style == 'none' then
         return {}
@@ -534,7 +534,7 @@ end
 ---@private
 ---@param row render.md.NodeInfo
 ---@return render.md.Mark
-M.render_table_delimiter = function(row)
+function M.render_table_delimiter(row)
     local pipe_table = state.config.pipe_table
     local border = pipe_table.border
     -- Order matters here, in particular handling inner intersections before left & right
@@ -563,7 +563,7 @@ end
 ---@param row render.md.NodeInfo
 ---@param highlight string
 ---@return render.md.Mark
-M.render_table_row = function(buf, row, highlight)
+function M.render_table_row(buf, row, highlight)
     local pipe_table = state.config.pipe_table
     local marks = {}
     if vim.tbl_contains({ 'raw', 'padded' }, pipe_table.cell) then
@@ -629,7 +629,7 @@ end
 ---@param first? render.md.NodeInfo
 ---@param last? render.md.NodeInfo
 ---@return render.md.Mark[]
-M.render_table_full = function(buf, delim, first, last)
+function M.render_table_full(buf, delim, first, last)
     local pipe_table = state.config.pipe_table
     local border = pipe_table.border
     if delim == nil or first == nil or last == nil then
@@ -690,7 +690,7 @@ end
 ---@param buf integer
 ---@param info render.md.NodeInfo
 ---@return integer
-M.table_visual_offset = function(buf, info)
+function M.table_visual_offset(buf, info)
     local result = ts.concealed(buf, info)
     local query = state.inline_link_query
     local tree = vim.treesitter.get_string_parser(info.text, 'markdown_inline')

Diff for: lua/render-markdown/handler/markdown_inline.lua

@@ -13,7 +13,7 @@ local M = {}
 ---@param root TSNode
 ---@param buf integer
 ---@return render.md.Mark[]
-M.parse = function(root, buf)
+function M.parse(root, buf)
     local marks = {}
     local query = state.inline_query
     for id, node in query:iter_captures(root, buf) do
@@ -36,7 +36,7 @@ end
 ---@private
 ---@param info render.md.NodeInfo
 ---@return render.md.Mark?
-M.render_code = function(info)
+function M.render_code(info)
     local code = state.config.code
     if not code.enabled then
         return nil
@@ -60,7 +60,7 @@ end
 ---@private
 ---@param info render.md.NodeInfo
 ---@return render.md.Mark?
-M.render_callout = function(info)
+function M.render_callout(info)
     local callout = component.callout(info.text, 'exact')
     if callout ~= nil then
         if not state.config.quote.enabled then
@@ -109,7 +109,7 @@ end
 ---@private
 ---@param info render.md.NodeInfo
 ---@return render.md.Mark?
-M.render_link = function(info)
+function M.render_link(info)
     local icon = shared.link_icon(info)
     if icon == nil then
         return nil

Diff for: lua/render-markdown/handler/shared.lua

@@ -8,7 +8,7 @@ local M = {}
 ---As a result table rendering needs to be painfully aware of this logic
 ---@param info render.md.NodeInfo
 ---@return string?
-M.link_icon = function(info)
+function M.link_icon(info)
     local link = state.config.link
     if not link.enabled then
         return nil

Diff for: lua/render-markdown/health.lua

@@ -23,19 +23,13 @@ function M.check()
     local has_treesitter = pcall(require, 'nvim-treesitter')
     if has_treesitter then
         vim.health.ok('installed')
-
-        M.check_parser('markdown')
-        M.check_parser('markdown_inline')
+        for _, language in ipairs({ 'markdown', 'markdown_inline' }) do
+            M.check_parser(language)
+            M.check_highlight(language)
+        end
         if latex.enabled then
             M.check_parser('latex', latex_advice)
         end
-
-        local highlight = require('nvim-treesitter.configs').get_module('highlight')
-        if highlight ~= nil and highlight.enable then
-            vim.health.ok('highlights enabled')
-        else
-            vim.health.error('highlights not enabled')
-        end
     else
         vim.health.error('not installed')
     end
@@ -71,16 +65,26 @@ function M.version(minimum, recommended)
     end
 end
 
----@param name string
+---@param language string
 ---@param advice string?
-function M.check_parser(name, advice)
+function M.check_parser(language, advice)
     local parsers = require('nvim-treesitter.parsers')
-    if parsers.has_parser(name) then
-        vim.health.ok(name .. ': parser installed')
+    if parsers.has_parser(language) then
+        vim.health.ok(language .. ': parser installed')
     elseif advice == nil then
-        vim.health.error(name .. ': parser not installed')
+        vim.health.error(language .. ': parser not installed')
+    else
+        vim.health.warn(language .. ': parser not installed', advice)
+    end
+end
+
+---@param language string
+function M.check_highlight(language)
+    local configs = require('nvim-treesitter.configs')
+    if configs.is_enabled('highlight', language, 0) then
+        vim.health.ok(language .. ': highlight enabled')
     else
-        vim.health.warn(name .. ': parser not installed', advice)
+        vim.health.error(language .. ': highlight not enabled')
     end
 end
 

Diff for: lua/render-markdown/icons.lua

@@ -7,7 +7,7 @@ local M = {}
 ---@param language string
 ---@return string?
 ---@return string?
-M.get = function(language)
+function M.get(language)
     if has_mini_icons then
         ---@diagnostic disable-next-line: return-type-mismatch
         return mini_icons.get('filetype', language)

Diff for: lua/render-markdown/init.lua

@@ -458,7 +458,7 @@ function M.setup(opts)
 end
 
 ---@param opts any
-M.command = function(opts)
+function M.command(opts)
     local args = opts.fargs
     if #args == 0 then
         M.enable()
@@ -477,15 +477,15 @@ M.command = function(opts)
     end
 end
 
-M.enable = function()
+function M.enable()
     manager.set_all(true)
 end
 
-M.disable = function()
+function M.disable()
     manager.set_all(false)
 end
 
-M.toggle = function()
+function M.toggle()
     manager.set_all(not state.enabled)
 end