Merge pull request #8014 from jakobandersen/utzig-named-variadic-arg

C, named variadic arg

CHANGES

@@ -43,6 +43,7 @@ Features added
   The warnings printed from this functionality can be suppressed by setting
   :confval:`c_warn_on_allowed_pre_v3`` to ``True``.
   The functionality is immediately deprecated.
+* #7999: C, add support for named variadic macro arguments.
 
 Bugs fixed
 ----------

sphinx/domains/c.py

@@ -1200,13 +1200,17 @@ class ASTTypeWithInit(ASTBase):
 
 
 class ASTMacroParameter(ASTBase):
-    def __init__(self, arg: ASTNestedName, ellipsis: bool = False) -> None:
+    def __init__(self, arg: ASTNestedName, ellipsis: bool = False,
+                 variadic: bool = False) -> None:
         self.arg = arg
         self.ellipsis = ellipsis
+        self.variadic = variadic
 
     def _stringify(self, transform: StringifyTransform) -> str:
         if self.ellipsis:
             return '...'
+        elif self.variadic:
+            return transform(self.arg) + '...'
         else:
             return transform(self.arg)
 
@@ -1215,6 +1219,9 @@ class ASTMacroParameter(ASTBase):
         verify_description_mode(mode)
         if self.ellipsis:
             signode += nodes.Text('...')
+        elif self.variadic:
+            name = str(self)
+            signode += nodes.emphasis(name, name)
         else:
             self.arg.describe_signature(signode, mode, env, symbol=symbol)
 
@@ -2915,9 +2922,16 @@ class DefinitionParser(BaseParser):
             if not self.match(identifier_re):
                 self.fail("Expected identifier in macro parameters.")
             nn = ASTNestedName([ASTIdentifier(self.matched_text)], rooted=False)
-            arg = ASTMacroParameter(nn)
-            args.append(arg)
+            # Allow named variadic args:
+            # https://gcc.gnu.org/onlinedocs/cpp/Variadic-Macros.html
             self.skip_ws()
+            if self.skip_string_and_ws('...'):
+                args.append(ASTMacroParameter(nn, False, True))
+                self.skip_ws()
+                if not self.skip_string(')'):
+                    self.fail('Expected ")" after "..." in macro parameters.')
+                break
+            args.append(ASTMacroParameter(nn))
             if self.skip_string_and_ws(','):
                 continue
             elif self.skip_string_and_ws(')'):

tests/test_domain_c.py

@@ -296,6 +296,10 @@ def test_macro_definitions():
     check('macro', 'M(arg, ...)', {1: 'M'})
     check('macro', 'M(arg1, arg2, ...)', {1: 'M'})
     check('macro', 'M(arg1, arg2, arg3, ...)', {1: 'M'})
+    # GNU extension
+    check('macro', 'M(arg1, arg2, arg3...)', {1: 'M'})
+    with pytest.raises(DefinitionError):
+        check('macro', 'M(arg1, arg2..., arg3)', {1: 'M'})
 
 
 def test_member_definitions():