Patch #1759: Backport of PEP 3129 class decorators

with some help from Georg

4 files changed, 127 insertions, 80 deletions

diff --git a/Lib/symbol.py b/Lib/symbol.py
index c650138..f25907b 100755
--- a/Lib/symbol.py
+++ b/Lib/symbol.py
@@ -15,85 +15,86 @@ file_input = 257
 eval_input = 258
 decorator = 259
 decorators = 260
-funcdef = 261
-parameters = 262
-varargslist = 263
-fpdef = 264
-fplist = 265
-stmt = 266
-simple_stmt = 267
-small_stmt = 268
-expr_stmt = 269
-augassign = 270
-print_stmt = 271
-del_stmt = 272
-pass_stmt = 273
-flow_stmt = 274
-break_stmt = 275
-continue_stmt = 276
-return_stmt = 277
-yield_stmt = 278
-raise_stmt = 279
-import_stmt = 280
-import_name = 281
-import_from = 282
-import_as_name = 283
-dotted_as_name = 284
-import_as_names = 285
-dotted_as_names = 286
-dotted_name = 287
-global_stmt = 288
-exec_stmt = 289
-assert_stmt = 290
-compound_stmt = 291
-if_stmt = 292
-while_stmt = 293
-for_stmt = 294
-try_stmt = 295
-with_stmt = 296
-with_var = 297
-except_clause = 298
-suite = 299
-testlist_safe = 300
-old_test = 301
-old_lambdef = 302
-test = 303
-or_test = 304
-and_test = 305
-not_test = 306
-comparison = 307
-comp_op = 308
-expr = 309
-xor_expr = 310
-and_expr = 311
-shift_expr = 312
-arith_expr = 313
-term = 314
-factor = 315
-power = 316
-atom = 317
-listmaker = 318
-testlist_gexp = 319
-lambdef = 320
-trailer = 321
-subscriptlist = 322
-subscript = 323
-sliceop = 324
-exprlist = 325
-testlist = 326
-dictmaker = 327
-classdef = 328
-arglist = 329
-argument = 330
-list_iter = 331
-list_for = 332
-list_if = 333
-gen_iter = 334
-gen_for = 335
-gen_if = 336
-testlist1 = 337
-encoding_decl = 338
-yield_expr = 339
+decorated = 261
+funcdef = 262
+parameters = 263
+varargslist = 264
+fpdef = 265
+fplist = 266
+stmt = 267
+simple_stmt = 268
+small_stmt = 269
+expr_stmt = 270
+augassign = 271
+print_stmt = 272
+del_stmt = 273
+pass_stmt = 274
+flow_stmt = 275
+break_stmt = 276
+continue_stmt = 277
+return_stmt = 278
+yield_stmt = 279
+raise_stmt = 280
+import_stmt = 281
+import_name = 282
+import_from = 283
+import_as_name = 284
+dotted_as_name = 285
+import_as_names = 286
+dotted_as_names = 287
+dotted_name = 288
+global_stmt = 289
+exec_stmt = 290
+assert_stmt = 291
+compound_stmt = 292
+if_stmt = 293
+while_stmt = 294
+for_stmt = 295
+try_stmt = 296
+with_stmt = 297
+with_var = 298
+except_clause = 299
+suite = 300
+testlist_safe = 301
+old_test = 302
+old_lambdef = 303
+test = 304
+or_test = 305
+and_test = 306
+not_test = 307
+comparison = 308
+comp_op = 309
+expr = 310
+xor_expr = 311
+and_expr = 312
+shift_expr = 313
+arith_expr = 314
+term = 315
+factor = 316
+power = 317
+atom = 318
+listmaker = 319
+testlist_gexp = 320
+lambdef = 321
+trailer = 322
+subscriptlist = 323
+subscript = 324
+sliceop = 325
+exprlist = 326
+testlist = 327
+dictmaker = 328
+classdef = 329
+arglist = 330
+argument = 331
+list_iter = 332
+list_for = 333
+list_if = 334
+gen_iter = 335
+gen_for = 336
+gen_if = 337
+testlist1 = 338
+encoding_decl = 339
+yield_expr = 340
 #--end constants--
 
 sym_name = {}
diff --git a/Lib/test/test_ast.py b/Lib/test/test_ast.py
index 14fc010..03dd5b5 100644
--- a/Lib/test/test_ast.py
+++ b/Lib/test/test_ast.py
@@ -156,7 +156,7 @@ def run_tests():
 #### EVERYTHING BELOW IS GENERATED #####
 exec_results = [
 ('Module', [('FunctionDef', (1, 0), 'f', ('arguments', [], None, None, []), [('Pass', (1, 9))], [])]),
-('Module', [('ClassDef', (1, 0), 'C', [], [('Pass', (1, 8))])]),
+('Module', [('ClassDef', (1, 0), 'C', [], [('Pass', (1, 8))], [])]),
 ('Module', [('FunctionDef', (1, 0), 'f', ('arguments', [], None, None, []), [('Return', (1, 8), ('Num', (1, 15), 1))], [])]),
 ('Module', [('Delete', (1, 0), [('Name', (1, 4), 'v', ('Del',))])]),
 ('Module', [('Assign', (1, 0), [('Name', (1, 0), 'v', ('Store',))], ('Num', (1, 4), 1))]),
diff --git a/Lib/test/test_decorators.py b/Lib/test/test_decorators.py
index 56aa5e1..cf2bc30 100644
--- a/Lib/test/test_decorators.py
+++ b/Lib/test/test_decorators.py
@@ -266,8 +266,44 @@ class TestDecorators(unittest.TestCase):
         self.assertEqual(bar(), 42)
         self.assertEqual(actions, expected_actions)
 
+class TestClassDecorators(unittest.TestCase):
+
+    def test_simple(self):
+        def plain(x):
+            x.extra = 'Hello'
+            return x
+        @plain
+        class C(object): pass
+        self.assertEqual(C.extra, 'Hello')
+
+    def test_double(self):
+        def ten(x):
+            x.extra = 10
+            return x
+        def add_five(x):
+            x.extra += 5
+            return x
+
+        @add_five
+        @ten
+        class C(object): pass
+        self.assertEqual(C.extra, 15)
+
+    def test_order(self):
+        def applied_first(x):
+            x.extra = 'first'
+            return x
+        def applied_second(x):
+            x.extra = 'second'
+            return x
+        @applied_second
+        @applied_first
+        class C(object): pass
+        self.assertEqual(C.extra, 'second')
+
 def test_main():
     test_support.run_unittest(TestDecorators)
+    test_support.run_unittest(TestClassDecorators)
 
 if __name__=="__main__":
     test_main()
diff --git a/Lib/test/test_grammar.py b/Lib/test/test_grammar.py
index d4bcfda..e2bb3eb 100644
--- a/Lib/test/test_grammar.py
+++ b/Lib/test/test_grammar.py
@@ -779,6 +779,16 @@ hello world
             def meth1(self): pass
             def meth2(self, arg): pass
             def meth3(self, a1, a2): pass
+        # decorator: '@' dotted_name [ '(' [arglist] ')' ] NEWLINE
+        # decorators: decorator+
+        # decorated: decorators (classdef | funcdef)
+        def class_decorator(x):
+            x.decorated = True
+            return x
+        @class_decorator
+        class G:
+            pass
+        self.assertEqual(G.decorated, True)
 
     def testListcomps(self):
         # list comprehension tests