parser: fix dotted decorator names

parser/grammar.y

@@ -332,7 +332,7 @@ optional_arglist_call:
 decorator:
 	'@' dotted_name optional_arglist_call NEWLINE
 	{
-		fn := &ast.Name{ExprBase: ast.ExprBase{Pos: $<pos>$}, Id: ast.Identifier($2), Ctx: ast.Load}
+		fn := dottedName($<pos>2, $2)
 		if $3 == nil {
 			$$ = fn
 		} else {

parser/grammar_data_test.go

@@ -320,6 +320,10 @@ var grammarTestData = []struct {
 	{"@dec(a,b,c=d,*args,**kwargs)\ndef fn():\n    pass\n", "exec", "Module(body=[FunctionDef(name='fn', args=arguments(args=[], vararg=None, kwonlyargs=[], kw_defaults=[], kwarg=None, defaults=[]), body=[Pass()], decorator_list=[Call(func=Name(id='dec', ctx=Load()), args=[Name(id='a', ctx=Load()), Name(id='b', ctx=Load())], keywords=[keyword(arg='c', value=Name(id='d', ctx=Load()))], starargs=Name(id='args', ctx=Load()), kwargs=Name(id='kwargs', ctx=Load()))], returns=None)])", nil, ""},
 	{"@dec1\n@dec2()\n@dec3(a)\n@dec4(a,b)\ndef fn():\n    pass\n", "exec", "Module(body=[FunctionDef(name='fn', args=arguments(args=[], vararg=None, kwonlyargs=[], kw_defaults=[], kwarg=None, defaults=[]), body=[Pass()], decorator_list=[Name(id='dec1', ctx=Load()), Call(func=Name(id='dec2', ctx=Load()), args=[], keywords=[], starargs=None, kwargs=None), Call(func=Name(id='dec3', ctx=Load()), args=[Name(id='a', ctx=Load())], keywords=[], starargs=None, kwargs=None), Call(func=Name(id='dec4', ctx=Load()), args=[Name(id='a', ctx=Load()), Name(id='b', ctx=Load())], keywords=[], starargs=None, kwargs=None)], returns=None)])", nil, ""},
 	{"@dec1\n@dec2()\n@dec3(a)\n@dec4(a,b)\nclass A(B):\n    pass\n", "exec", "Module(body=[ClassDef(name='A', bases=[Name(id='B', ctx=Load())], keywords=[], starargs=None, kwargs=None, body=[Pass()], decorator_list=[Name(id='dec1', ctx=Load()), Call(func=Name(id='dec2', ctx=Load()), args=[], keywords=[], starargs=None, kwargs=None), Call(func=Name(id='dec3', ctx=Load()), args=[Name(id='a', ctx=Load())], keywords=[], starargs=None, kwargs=None), Call(func=Name(id='dec4', ctx=Load()), args=[Name(id='a', ctx=Load()), Name(id='b', ctx=Load())], keywords=[], starargs=None, kwargs=None)])])", nil, ""},
+	{"@a.b\ndef fn():\n    pass\n", "exec", "Module(body=[FunctionDef(name='fn', args=arguments(args=[], vararg=None, kwonlyargs=[], kw_defaults=[], kwarg=None, defaults=[]), body=[Pass()], decorator_list=[Attribute(value=Name(id='a', ctx=Load()), attr='b', ctx=Load())], returns=None)])", nil, ""},
+	{"@a.b.c(d,e=f)\ndef fn():\n    pass\n", "exec", "Module(body=[FunctionDef(name='fn', args=arguments(args=[], vararg=None, kwonlyargs=[], kw_defaults=[], kwarg=None, defaults=[]), body=[Pass()], decorator_list=[Call(func=Attribute(value=Attribute(value=Name(id='a', ctx=Load()), attr='b', ctx=Load()), attr='c', ctx=Load()), args=[Name(id='d', ctx=Load())], keywords=[keyword(arg='e', value=Name(id='f', ctx=Load()))], starargs=None, kwargs=None)], returns=None)])", nil, ""},
+	{"@a.b\n@c.d()\n@e\nclass A(B):\n    pass\n", "exec", "Module(body=[ClassDef(name='A', bases=[Name(id='B', ctx=Load())], keywords=[], starargs=None, kwargs=None, body=[Pass()], decorator_list=[Attribute(value=Name(id='a', ctx=Load()), attr='b', ctx=Load()), Call(func=Attribute(value=Name(id='c', ctx=Load()), attr='d', ctx=Load()), args=[], keywords=[], starargs=None, kwargs=None), Name(id='e', ctx=Load())])])", nil, ""},
+	{"@a.\ndef fn():\n    pass\n", "exec", "", py.SyntaxError, "invalid syntax"},
 	{"", "single", "", py.SyntaxError, "unexpected EOF while parsing"},
 	{"\n", "single", "", py.SyntaxError, "unexpected EOF while parsing"},
 	{"pass\n", "single", "Interactive(body=[Pass()])", nil, ""},

parser/make_grammar_test.py

@@ -470,6 +470,28 @@ def fn():
 class A(B):
     pass
 """, "exec"),
+    ("""\
+@a.b
+def fn():
+    pass
+""", "exec"),
+    ("""\
+@a.b.c(d,e=f)
+def fn():
+    pass
+""", "exec"),
+    ("""\
+@a.b
+@c.d()
+@e
+class A(B):
+    pass
+""", "exec"),
+    ("""\
+@a.
+def fn():
+    pass
+""", "exec", SyntaxError),
 
     # single input
     ("", "single", SyntaxError),

parser/parser.go

@@ -9,3 +9,21 @@
 
 //go:generate goyacc -v y.output grammar.y
 package parser
+
+import (
+	"strings"
+
+	"github.com/go-python/gpython/ast"
+)
+
+// dottedName returns the expression for a dotted name such as "a.b.c": a
+// Name for the first part and an Attribute for each further part, all at
+// pos, as ast_for_dotted_name does in CPython.
+func dottedName(pos ast.Pos, name string) ast.Expr {
+	parts := strings.Split(name, ".")
+	var expr ast.Expr = &ast.Name{ExprBase: ast.ExprBase{Pos: pos}, Id: ast.Identifier(parts[0]), Ctx: ast.Load}
+	for _, part := range parts[1:] {
+		expr = &ast.Attribute{ExprBase: ast.ExprBase{Pos: pos}, Value: expr, Attr: ast.Identifier(part), Ctx: ast.Load}
+	}
+	return expr
+}

vm/tests/decorators.py

@@ -107,12 +107,11 @@ def notamethod(x):
 self.assertRaises(TypeError, notamethod, 1)
 
 doc="test_dotted"
-# FIXME class decorator
-# decorators = MiscDecorators()
-# @decorators.author('Cleese')
-# def foo(): return 42
-# self.assertEqual(foo(), 42)
-# self.assertEqual(foo.author, 'Cleese')
+decorators = MiscDecorators()
+@decorators.author('Cleese')
+def foo(): return 42
+self.assertEqual(foo(), 42)
+self.assertEqual(foo.author, 'Cleese')
 
 doc="test_argforms"
 def noteargs(*args, **kwds):
@@ -198,7 +197,7 @@ def unimp(func):
 
 for expr, exc in [ ("undef", NameError),
                    ("nullval", TypeError),
-                   ("nullval.attr", NameError), # FIXME    ("nullval.attr", AttributeError),
+                   ("nullval.attr", AttributeError),
                    ("unimp", NotImplementedError)]:
     codestr = "@%s\ndef f(): pass\nassert f() is None" % expr
     code = compile(codestr, "test", "exec")
@@ -244,53 +243,53 @@ def foo(): return 42
 # performed in the above order for each decorator, but we should
 # iterate through the decorators in the reverse of the order they
 # appear in the source.
-# FIXME class decorator
-# actions = []
-#
-# def make_decorator(tag):
-#     actions.append('makedec' + tag)
-#     def decorate(func):
-#         actions.append('calldec' + tag)
-#         return func
-#     return decorate
-#
-# class NameLookupTracer (object):
-#     def __init__(self, index):
-#         self.index = index
-#
-#     def __getattr__(self, fname):
-#         if fname == 'make_decorator':
-#             opname, res = ('evalname', make_decorator)
-#         elif fname == 'arg':
-#             opname, res = ('evalargs', str(self.index))
-#         else:
-#             assert False, "Unknown attrname %s" % fname
-#         actions.append('%s%d' % (opname, self.index))
-#         return res
-#
-# c1, c2, c3 = map(NameLookupTracer, [ 1, 2, 3 ])
-#
-# expected_actions = [ 'evalname1', 'evalargs1', 'makedec1',
-#                      'evalname2', 'evalargs2', 'makedec2',
-#                      'evalname3', 'evalargs3', 'makedec3',
-#                      'calldec3', 'calldec2', 'calldec1' ]
-#
-# actions = []
-# @c1.make_decorator(c1.arg)
-# @c2.make_decorator(c2.arg)
-# @c3.make_decorator(c3.arg)
-# def foo(): return 42
-# self.assertEqual(foo(), 42)
-#
-# self.assertEqual(actions, expected_actions)
+
+actions = []
+
+def make_decorator(tag):
+    actions.append('makedec' + tag)
+    def decorate(func):
+        actions.append('calldec' + tag)
+        return func
+    return decorate
+
+class NameLookupTracer (object):
+    def __init__(self, index):
+        self.index = index
+
+    def __getattr__(self, fname):
+        if fname == 'make_decorator':
+            opname, res = ('evalname', make_decorator)
+        elif fname == 'arg':
+            opname, res = ('evalargs', str(self.index))
+        else:
+            assert False, "Unknown attrname %s" % fname
+        actions.append('%s%d' % (opname, self.index))
+        return res
+
+c1, c2, c3 = map(NameLookupTracer, [ 1, 2, 3 ])
+
+expected_actions = [ 'evalname1', 'evalargs1', 'makedec1',
+                     'evalname2', 'evalargs2', 'makedec2',
+                     'evalname3', 'evalargs3', 'makedec3',
+                     'calldec3', 'calldec2', 'calldec1' ]
+
+actions = []
+@c1.make_decorator(c1.arg)
+@c2.make_decorator(c2.arg)
+@c3.make_decorator(c3.arg)
+def foo(): return 42
+self.assertEqual(foo(), 42)
+
+self.assertEqual(actions, expected_actions)
+
+# Test the equivalence claim in chapter 7 of the reference manual.
 #
-# # Test the equivalence claim in chapter 7 of the reference manual.
-# #
-# actions = []
-# def bar(): return 42
-# bar = c1.make_decorator(c1.arg)(c2.make_decorator(c2.arg)(c3.make_decorator(c3.arg)(bar)))
-# self.assertEqual(bar(), 42)
-# self.assertEqual(actions, expected_actions)
+actions = []
+def bar(): return 42
+bar = c1.make_decorator(c1.arg)(c2.make_decorator(c2.arg)(c3.make_decorator(c3.arg)(bar)))
+self.assertEqual(bar(), 42)
+self.assertEqual(actions, expected_actions)
 
 doc="test_simple"
 def plain(x):