feat: add support for vim help files (#164)

lua/aerial/backends/treesitter/extensions.lua

@@ -119,6 +119,62 @@ M.markdown = {
   end,
 }
 
+M.help = {
+  _get_level = function(node)
+    local level_str = node:type():match("^h(%d+)$")
+    if level_str then
+      return tonumber(level_str)
+    else
+      return 99
+    end
+  end,
+  get_parent = function(stack, match, node)
+    -- Fix the symbol nesting
+    local level = M.help._get_level(node)
+    for i = #stack, 1, -1 do
+      local last = stack[i]
+      if M.help._get_level(last.node) < level then
+        return last.item, last.node, i
+      else
+        table.remove(stack, i)
+      end
+    end
+    return nil, nil, 0
+  end,
+  postprocess = function(bufnr, item, match)
+    -- The name node of headers only captures the final node.
+    -- We need to get _all_ word nodes
+    local pieces = {}
+    local node = match.name.node
+    if vim.startswith(match.type.node:type(), "h") then
+      while node and node:type() == "word" do
+        local row, col = node:start()
+        table.insert(pieces, 1, get_node_text(node, bufnr))
+        node = node:prev_sibling()
+        item.lnum = row + 1
+        item.col = col
+      end
+      item.name = table.concat(pieces, " ")
+    end
+  end,
+  postprocess_symbols = function(bufnr, items)
+    -- Sometimes helpfiles have a bunch of tags at the top in the same line. Collapse them.
+    while #items > 1 and items[1].lnum == items[2].lnum do
+      table.remove(items, 2)
+    end
+    -- Remove the first tag under a header IF that tag appears on the same line
+    for _, item in ipairs(items) do
+      if item.children and item.children[1] then
+        local child = item.children[1]
+        if child.lnum == item.lnum then
+          table.remove(item.children, 1)
+        end
+        M.help.postprocess_symbols(bufnr, item.children)
+      end
+    end
+  end,
+}
+
 M.rust = {
   postprocess = function(bufnr, item, match)
     if item.kind == "Class" then

lua/aerial/backends/treesitter/init.lua

@@ -62,12 +62,12 @@ M.fetch_symbols_sync = function(bufnr)
   local ext = extensions[lang]
   local kind_map = language_kind_map[lang]
   for match in query.iter_group_results(bufnr, "aerial", syntax_tree:root(), lang) do
-    local name_node = (utils.get_at_path(match, "name") or {}).node
-    local type_node = (utils.get_at_path(match, "type") or {}).node
+    local name_node = (match.name or {}).node
+    local type_node = (match.type or {}).node
     -- The location capture groups are optional. We default to the
     -- location of the @type capture
-    local start_node = (utils.get_at_path(match, "start") or {}).node or type_node
-    local end_node = (utils.get_at_path(match, "end") or {}).node or start_node
+    local start_node = (match.start or {}).node or type_node
+    local end_node = (match["end"] or {}).node or start_node
     local parent_item, parent_node, level = ext.get_parent(stack, match, type_node)
     -- Sometimes our queries will match the same node twice.
     -- Detect that (type_node == parent_node), and skip dupes.

lua/aerial/backends/treesitter/language_kind_map.lua

@@ -38,6 +38,11 @@ return {
     method_declaration = "Method",
     struct_type = "Struct",
   },
+  help = {
+    h1 = "Interface",
+    h2 = "Interface",
+    tag = "Interface",
+  },
   java = {
     class_declaration = "Class",
     enum_declaration = "Enum",

queries/help/aerial.scm

@@ -0,0 +1,13 @@
+(h1
+  (word)+ @name @start
+  (tag)
+) @type
+
+(h2
+  (word)+ @name @start
+  (tag)
+) @type
+
+(tag
+  text: (word) @name
+) @type

tests/treesitter/help_spec.lua

@@ -0,0 +1,37 @@
+local util = require("tests.test_util")
+
+describe("treesitter help", function()
+  it("parses all symbols correctly", function()
+    util.test_file_symbols("treesitter", "./tests/treesitter/help_test.txt", {
+      {
+        kind = "Interface",
+        name = "help_test.txt",
+        level = 0,
+        lnum = 1,
+        col = 0,
+        end_lnum = 1,
+        end_col = 15,
+      },
+      {
+        kind = "Interface",
+        name = "TEST INTRO",
+        level = 0,
+        lnum = 3,
+        col = 0,
+        end_lnum = 3,
+        end_col = 10,
+        children = {
+          {
+            kind = "Interface",
+            name = ":SomeCommand",
+            level = 1,
+            lnum = 5,
+            col = 68,
+            end_lnum = 5,
+            end_col = 82,
+          },
+        },
+      },
+    })
+  end)
+end)

tests/treesitter/help_test.txt

@@ -0,0 +1,9 @@
+*help_test.txt* *help_test*
+--------------------------------------------------------------------------------
+TEST INTRO                                                            *test-intro*
+
+SomeCommand                                                         *:SomeCommand*
+    Description of the command
+
+================================================================================
+vim:tw=80:ts=2:ft=help:norl:syntax=help: