Support for PEP 614

Grammar/python.gram

@@ -208,7 +208,7 @@ kwds[arg_ty]:
     | '**' a=plain_name { a }
 annotation[expr_ty]: expression
 
-decorators[asdl_seq*]: a=('@' f=factor NEWLINE { f })+ { a }
+decorators[asdl_seq*]: a=('@' f=named_expression NEWLINE { f })+ { a }
 
 class_def[stmt_ty]:
     | a=decorators b=class_def_raw { class_def_decorators(p, a, b) }

Lib/test/test_peg_parser.py

@@ -53,6 +53,19 @@ class C(A, B):
         class C:
             pass
      '''),
+    ('class_def_decorator_with_expression',
+     '''
+        @lambda x: 42
+        class C:
+            pass
+     '''),
+    ('class_def_decorator_with_expression_and_walrus',
+     '''
+        @x:=lambda x: 42
+        class C:
+            pass
+     '''),
+
     ('class_def_keywords',
      '''
         class C(keyword=a+b, **c):
@@ -102,6 +115,18 @@ def f():
         async def d():
             pass
      '''),
+    ('decorator_with_expression',
+     '''
+        @lambda x: 42
+        def f():
+            pass
+     '''),
+    ('decorator_with_expression_and_walrus',
+     '''
+        @x:=lambda x: 42
+        def f():
+            pass
+     '''),
     ('del_attribute', 'del a.b'),
     ('del_call_attribute', 'del a().c'),
     ('del_call_genexp_attribute', 'del a(i for i in b).c'),

Parser/pegen/parse.c

@@ -3612,15 +3612,15 @@ annotation_rule(Parser *p)
     return res;
 }
 
-// decorators: (('@' factor NEWLINE))+
+// decorators: (('@' named_expression NEWLINE))+
 static asdl_seq*
 decorators_rule(Parser *p)
 {
     asdl_seq* res = NULL;
     if (is_memoized(p, decorators_type, &res))
         return res;
     int mark = p->mark;
-    { // (('@' factor NEWLINE))+
+    { // (('@' named_expression NEWLINE))+
         asdl_seq * a;
         if (
             (a = _loop1_61_rule(p))
@@ -11122,7 +11122,7 @@ _tmp_60_rule(Parser *p)
     return res;
 }
 
-// _loop1_61: ('@' factor NEWLINE)
+// _loop1_61: ('@' named_expression NEWLINE)
 static asdl_seq *
 _loop1_61_rule(Parser *p)
 {
@@ -11137,7 +11137,7 @@ _loop1_61_rule(Parser *p)
     }
     ssize_t children_capacity = 1;
     ssize_t n = 0;
-    { // ('@' factor NEWLINE)
+    { // ('@' named_expression NEWLINE)
         void *_tmp_116_var;
         while (
             (_tmp_116_var = _tmp_116_rule(p))
@@ -13254,22 +13254,22 @@ _tmp_115_rule(Parser *p)
     return res;
 }
 
-// _tmp_116: '@' factor NEWLINE
+// _tmp_116: '@' named_expression NEWLINE
 static void *
 _tmp_116_rule(Parser *p)
 {
     void * res = NULL;
     if (is_memoized(p, _tmp_116_type, &res))
         return res;
     int mark = p->mark;
-    { // '@' factor NEWLINE
+    { // '@' named_expression NEWLINE
         expr_ty f;
         void *literal;
         void *newline_var;
         if (
             (literal = expect_token(p, 49))
             &&
-            (f = factor_rule(p))
+            (f = named_expression_rule(p))
             &&
             (newline_var = newline_token(p))
         )