feat: support help file

README.md

@@ -11,11 +11,11 @@ An extension for [telescope.nvim](https://github.com/nvim-telescope/telescope.nv
 ## Supported File Type
 
 - Markdown, including `vimwiki`, `vim-pandoc-syntax`, and `vim-gfm-syntax`.
-- AsciiDoc (experimental)
-- LaTeX (experimental)
-- OrgMode (experimental)
-- ReStructuredText (experimental)
-- Vim Help (experimental)
+- AsciiDoc
+- LaTeX
+- OrgMode
+- ReStructuredText
+- Vim Help
 
 ## Setup
 
@@ -30,20 +30,46 @@ You can setup the extension by adding the following to your config:
 require('telescope').load_extension('heading')
 ```
 
-Use treesitter (which only supports Markdown/ReStructuredText) to query headings. Setup with `telescope.setup` **before** `load_extension`:
+### Tree-sitter Support
+
+telescope-heading supports Tree-sitter for parsing documents and finding headings.
+
+File types with Tree-sitter supports:
+- Markdown
+- ReStructuredText
+- Vim Help
+
 ```lua
+-- add nvim-treesitter
+use('nvim-treesitter/nvim-treesitter')
+
+-- make sure you have already installed treesitter modules
+require('nvim-treesitter.configs').setup({
+    ensure_installed = {
+        -- ..
+        'markdown',
+        'rst',
+        -- ..
+    },
+})
+
+-- enable treesitter parsing
 local telescope = require('telescope')
 telescope.setup({
-    -- other setups
+    -- ...
     extensions = {
         heading = {
             treesitter = true,
         },
     },
 })
 
+-- `load_extension` must be after `telescope.setup`
+telescope.load_extension('heading')
 ```
 
+If nvim-treesitter is not correctly loaded, it will fallback to normal parsing.
+
 ## Usage
 
 ```viml

lua/telescope/_extensions/heading/format/help.lua

@@ -43,4 +43,27 @@ function Help.get_headings(filepath, start, total)
     return headings
 end
 
+function Help.ts_get_headings(filepath, bufnr)
+    local ts = vim.treesitter
+    local query = [[
+    (headline (word)) @headline_title
+    ]]
+    local parsed_query = ts.parse_query('help', query)
+    local parser = ts.get_parser(bufnr, 'help')
+    local root = parser:parse()[1]:root()
+    local start_row, _, end_row, _ = root:range()
+
+    local headings = {}
+    for _, node in parsed_query:iter_captures(root, bufnr, start_row, end_row) do
+        local row, _ = node:range()
+        local line = vim.fn.getline(row + 2)
+        table.insert(headings, {
+            heading = vim.trim(line),
+            line = row + 2,
+            path = filepath,
+        })
+    end
+    return headings
+end
+
 return Help