feat: add hover support for member access with comments

- Add member access chain resolution in hover handler
- Parse #var.member.submember notation and resolve type chain
- Show member comments in hover tooltip
- Extract comments from UDT and DB file fields
- Combine all type sources (doc.types, external_types, builtin)

src/main.lua

@@ -313,6 +313,165 @@ function handlers.textDocument_hover(params)
 	local line = lines[line_idx]
 	local col = params.position.character + 1
 
+	-- Helper to resolve member path and get member info with comments
+	local function resolve_member_path(root_type, member_path, types)
+		if not root_type or not member_path or member_path == "" then
+			return nil
+		end
+
+		local parts = {}
+		for part in member_path:gmatch("[^.]+") do
+			table.insert(parts, part)
+		end
+
+		if #parts == 0 then
+			return nil
+		end
+
+		local current_type = root_type:gsub('"', '')
+		local current_member = nil
+
+		for i, part in ipairs(parts) do
+			local type_info = types and types[current_type]
+			if not type_info then
+				-- Try built-in types
+				local builtin_params = builtin.get_parameters(current_type)
+				if builtin_params then
+					local fields = builtin_params.inputs or {}
+					for _, field in ipairs(fields) do
+						if field.name == part then
+							current_member = field
+							current_type = field.type and field.type:gsub('"', '') or current_type
+							break
+						end
+					end
+					if current_member then
+						-- Continue to next part
+					else
+						return nil
+					end
+				else
+					return nil
+				end
+			else
+				local found = false
+				local fields = type_info.fields or type_info.inputs or {}
+				for _, field in ipairs(fields) do
+					if field.name == part then
+						current_member = field
+						current_type = field.type and field.type:gsub('"', '') or current_type
+						found = true
+						break
+					end
+				end
+
+				if not found then
+					return nil
+				end
+			end
+		end
+
+		return current_member
+	end
+
+	-- Check if we're in a member access chain (e.g., #var.member1.member2)
+	local function find_member_access_chain()
+		local chain_start = col
+		while chain_start > 1 do
+			local ch = line:sub(chain_start - 1, chain_start - 1)
+			if ch:match("[%w_.#]") then
+				chain_start = chain_start - 1
+			else
+				break
+			end
+		end
+
+		local chain_end = col
+		while chain_end <= #line do
+			local ch = line:sub(chain_end, chain_end)
+			if ch:match("[%w_.]") then
+				chain_end = chain_end + 1
+			else
+				break
+			end
+		end
+
+		local chain = line:sub(chain_start, chain_end - 1)
+		
+		-- Check if this is a member access (contains .)
+		if not chain:match("%.") then
+			return nil, nil, chain_start, chain_end
+		end
+
+		-- Parse the chain: #var.member1.member2
+		local root_var = chain:match("#([%w_]+)")
+		if not root_var then
+			-- Try without # (for global DB access)
+			root_var = chain:match("^([%w_]+)%.")
+		end
+
+		if root_var then
+			local member_path = chain:match("%.(.+)$")
+			return root_var, member_path, chain_start, chain_end
+		end
+
+		return nil, nil, chain_start, chain_end
+	end
+
+	-- Try member access first
+	local root_var, member_path, chain_start, chain_end = find_member_access_chain()
+	if root_var and member_path and doc.variables and doc.variables[root_var] then
+		local var_info = doc.variables[root_var]
+		local root_type = var_info.data_type
+
+		if root_type then
+			root_type = root_type:gsub('"', '')
+			local all_types = {}
+			
+			-- Combine all type sources
+			if doc.types then
+				for k, v in pairs(doc.types) do
+					all_types[k] = v
+				end
+			end
+			
+			local external_types = plc_json.get_types(doc.root_dir or "")
+			for k, v in pairs(external_types) do
+				if not all_types[k] then
+					all_types[k] = v
+				end
+			end
+
+			local member = resolve_member_path(root_type, member_path, all_types)
+			if member then
+				local detail = string.format("**Member**: `%s`\nType: `%s`",
+					member.name, member.type or "unknown")
+				if member.comment and member.comment ~= "" then
+					detail = detail .. "\n\n" .. member.comment
+				end
+				detail = detail .. string.format("\n\n*From: `#%s.%s`*", root_var, member_path)
+
+				-- Find the actual word range for highlighting
+				local member_word_start = col
+				while member_word_start > 1 and line:sub(member_word_start - 1, member_word_start - 1):match("[%w_]") do
+					member_word_start = member_word_start - 1
+				end
+				local member_word_end = col
+				while member_word_end <= #line and line:sub(member_word_end, member_word_end):match("[%w_]") do
+					member_word_end = member_word_end + 1
+				end
+
+				return {
+					contents = { kind = "markdown", value = detail },
+					range = {
+						start = { line = params.position.line, character = member_word_start - 1 },
+						["end"] = { line = params.position.line, character = member_word_end - 1 },
+					},
+				}
+			end
+		end
+	end
+
 	local word_start = col
 	while word_start > 1 and line:sub(word_start - 1, word_start - 1):match("[%w_]") do
 		word_start = word_start - 1

src/plc_json.lua

@@ -212,9 +212,11 @@ local function parse_scl_type_file(content)
           local field_name = line:match("^%s*(%w+)%s*:")
           if field_name and field_name ~= "END_STRUCT" then
             local field_type = line:match(":%s*([%w_]+)")
+            local field_comment = line:match("//%s*(.+)$") or line:match("%(%*(.-)%*%)")
             table.insert(types[current_type_name].fields, {
               name = field_name,
               type = field_type or "unknown",
+              comment = field_comment,
             })
           end
         end
@@ -254,10 +256,12 @@ local function parse_db_file(content)
       local field_name = line:match("^%s*(%w+)%s*:")
       if field_name then
         local field_type = line:match(":%s*([%w_]+)")
+        local field_comment = line:match("//%s*(.+)$") or line:match("%(%*(.-)%*%)")
         if field_type then
           table.insert(types[current_type_name].fields, {
             name = field_name,
             type = field_type,
+            comment = field_comment,
           })
         end
       end