Improve EnumerationNamespaces and CodeGenerator.enum_aliases (ent…

…hought#543)

* update `enum_aliases`

* add `__bool__` to `EnumerationNamespaces`

* update `CodeGenerator.EnumValue`

* add conditional branches for no enums in the typelib

comtypes/tools/codegenerator.py

@@ -445,7 +445,7 @@ def __init__(self, known_symbols=None, known_interfaces=None) -> None:
         self.done = set()  # type descriptions that have been generated
         self.names = set()  # names that have been generated
         self.externals = []  # typelibs imported to generated module
-        self.aliases: Dict[str, str] = {}
+        self.enum_aliases: Dict[str, str] = {}
         self.last_item_class = False
 
     def generate(self, item):
@@ -594,7 +594,14 @@ def generate_wrapper_code(
             for n, v in self.unnamed_enum_members:
                 print(f"{n} = {v}", file=output)
             print(file=output)
-        print(self.enums.to_constants(), file=output)
+        if self.enums:
+            print(self.enums.to_constants(), file=output)
+            print(file=output)
+        if self.enum_aliases:
+            print("# aliases for enums", file=output)
+            for k, v in self.enum_aliases.items():
+                print(f"{k} = {v}", file=output)
+            print(file=output)
         print(self.stream.getvalue(), file=output)
         print(self._make_dunder_all_part(), file=output)
         print(file=output)
@@ -619,12 +626,12 @@ def generate_friendly_code(self, modname: str) -> str:
         print(self._make_friendly_module_import_part(modname), file=output)
         print(file=output)
         print(file=output)
-        print(self.enums.to_intflags(), file=output)
-        print(file=output)
-        print(file=output)
-        enum_aliases = self.enum_aliases
-        if enum_aliases:
-            for k, v in enum_aliases.items():
+        if self.enums:
+            print(self.enums.to_intflags(), file=output)
+            print(file=output)
+            print(file=output)
+        if self.enum_aliases:
+            for k, v in self.enum_aliases.items():
                 print(f"{k} = {v}", file=output)
             print(file=output)
             print(file=output)
@@ -662,10 +669,6 @@ def _make_friendly_module_import_part(self, modname: str) -> str:
             part = f"from {modname} import (\n{joined_names}\n)"
         return part
 
-    @property
-    def enum_aliases(self) -> Dict[str, str]:
-        return {k: v for k, v in self.aliases.items() if v in self.enums}
-
     def need_VARIANT_imports(self, value):
         text = repr(value)
         if "Decimal(" in text:
@@ -690,7 +693,7 @@ def EnumValue(self, tp: typedesc.EnumValue) -> None:
         if keyword.iskeyword(tp.name):
             # XXX use logging!
             if __warn_on_munge__:
-                print("# Fixing keyword as EnumValue for %s" % tp.name)
+                print(f"# Fixing keyword as EnumValue for {tp.name}")
         tp_name = self._to_type_name(tp)
         if tp.enumeration.name:
             self.enums.add(tp.enumeration.name, tp_name, value)
@@ -716,9 +719,11 @@ def Typedef(self, tp: typedesc.Typedef) -> None:
             if definition in self.known_symbols:
                 self.declarations.add(tp.name, definition)
             else:
-                print("%s = %s" % (tp.name, definition), file=self.stream)
-                self.aliases[tp.name] = definition
-                self.last_item_class = False
+                if isinstance(tp.typ, typedesc.Enumeration):
+                    self.enum_aliases[tp.name] = definition
+                else:
+                    print(f"{tp.name} = {definition}", file=self.stream)
+                    self.last_item_class = False
         self.names.add(tp.name)
 
     def FundamentalType(self, item: typedesc.FundamentalType) -> None:
@@ -1610,7 +1615,9 @@ def add(self, enum_name: str, member_name: str, value: int) -> None:
         Examples:
             <BLANKLINE> is necessary for doctest
             >>> enums = EnumerationNamespaces()
+            >>> assert not enums
             >>> enums.add('Foo', 'ham', 1)
+            >>> assert enums
             >>> enums.add('Foo', 'spam', 2)
             >>> enums.add('Bar', 'bacon', 3)
             >>> assert 'Foo' in enums
@@ -1638,6 +1645,9 @@ class Bar(IntFlag):
     def __contains__(self, item: str) -> bool:
         return item in self.data
 
+    def __bool__(self) -> bool:
+        return bool(self.data)
+
     def get_symbols(self) -> Set[str]:
         return set(self.data)