diff --git a/apps/twnlua/docgen.py b/apps/twnlua/docgen.py
index a57aba1..734443e 100755
--- a/apps/twnlua/docgen.py
+++ b/apps/twnlua/docgen.py
@@ -7,9 +7,11 @@ with open(sys.argv[1], 'r') if sys.argv[1] != "-" else sys.stdin as f:
 
 api = json.loads(api_source)
 
-def to_lua_type_annot(typename):
-    basetype = typename.rsplit(' *', 1)[0]
-    if typename == "char *":
+def to_lua_type_annot(typedesc):
+    if type(typedesc) is dict:
+        return r'{ %s }' % ','.join('%s: %s' % (f["name"], to_lua_type_annot(f["type"])) for f in typedesc["fields"])
+    basetype = typedesc.rsplit(' *', 1)[0]
+    if typedesc == "char *":
         return "string"
     elif basetype == "float":
         return "number"
@@ -27,7 +29,7 @@ def to_lua_type_annot(typename):
         return r"{ x: number, y: number, w: number, h: number }"
     else:
         return "unknown"
-        # raise BaseException("Unhandled type for annotation: %s" % typename)
+        # raise BaseException("Unhandled type for annotation: %s" % typedesc)
 
 type_annotations, enum_annotations = {}, {}
 type_annotations["ctx"] = r"{ %s, udata: table }" % \
@@ -45,9 +47,14 @@ for annot in enum_annotations:
 
 procedure_annotations = {}
 for procedure, procedure_desc in api["procedures"].items():
-    procedure_annotations[procedure] = r"{ %s }" % \
+    procedure_annotations[procedure] = {}
+    procedure_annotations[procedure]["params"] = r"{ %s }" % \
         ', '.join("%s: %s" % (p["name"], to_lua_type_annot(p["type"]) + '?' * ("default" in p)) for p in procedure_desc["params"])
+    if "return" in procedure_desc:
+        procedure_annotations[procedure]["return"] = to_lua_type_annot(procedure_desc["return"])
 
 for annot in procedure_annotations:
-    print("---@param args " + procedure_annotations[annot])
+    print("---@param args " + procedure_annotations[annot]["params"])
+    if "return" in procedure_annotations[annot]:
+        print("---@return " + procedure_annotations[annot]["return"])
     print("function %s(args) end" % annot)