Fixes and testcases for issue #27

astor/codegen.py

@@ -126,13 +126,13 @@ class SourceGenerator(ExplicitNodeVisitor):
 
         loop_args(node.args, node.defaults)
         self.conditional_write(write_comma, '*', node.vararg)
-        self.conditional_write(write_comma, '**', node.kwarg)
 
         kwonlyargs = getattr(node, 'kwonlyargs', None)
         if kwonlyargs:
             if node.vararg is None:
                 self.write(write_comma, '*')
             loop_args(kwonlyargs, node.kw_defaults)
+        self.conditional_write(write_comma, '**', node.kwarg)
 
     def statement(self, node, *params, **kw):
         self.newline(node)
@@ -168,7 +168,7 @@ class SourceGenerator(ExplicitNodeVisitor):
             self.statement(node, 'from ', node.level * '.',
                            node.module, ' import ')
         else:
-            self.statement(node, 'from ', node.level * '. import ')
+            self.statement(node, 'from ', node.level * '.', ' import ')
         self.comma_list(node.names)
 
     def visit_Import(self, node):
@@ -307,10 +307,10 @@ class SourceGenerator(ExplicitNodeVisitor):
         self.body(node.body)
         for handler in node.handlers:
             self.visit(handler)
+        self.else_body(node.orelse)
         if node.finalbody:
             self.statement(node, 'finally:')
             self.body(node.finalbody)
-        self.else_body(node.orelse)
 
     def visit_ExceptHandler(self, node):
         self.statement(node, 'except')
@@ -367,7 +367,10 @@ class SourceGenerator(ExplicitNodeVisitor):
     # Expressions
 
     def visit_Attribute(self, node):
-        self.write(node.value, '.', node.attr)
+        if isinstance(node.value, ast.Num):
+            self.write('(', node.value, ')', '.', node.attr)
+        else:
+            self.write(node.value, '.', node.attr)
 
     def visit_Call(self, node):
         want_comma = []
@@ -473,14 +476,19 @@ class SourceGenerator(ExplicitNodeVisitor):
     def visit_ExtSlice(self, node):
         self.comma_list(node.dims, len(node.dims) == 1)
 
-    def visit_Yield(self, node):
+    def visit_Yield(self, node, dofrom=False):
+        is_stmt = self.new_lines
+        if not is_stmt:
+            self.write('(')
         self.write('yield')
+        self.conditional_write(' from' if dofrom else None)
         self.conditional_write(' ', node.value)
+        if not is_stmt:
+            self.write(')')
 
     # new for Python 3.3
     def visit_YieldFrom(self, node):
-        self.write('yield from ')
-        self.visit(node.value)
+        self.visit_Yield(node, True)
 
     # new for Python 3.5
     def visit_Await(self, node):

tests/test_codegen.py

@@ -23,10 +23,12 @@ class CodegenTestCase(unittest.TestCase):
     def assertAstSourceEqual(self, source):
         self.assertEqual(astor.to_source(ast.parse(source)), source)
 
-    def assertAstSourceEqualIfAtLeastVersion(self, source, version_tuple):
+    def assertAstSourceEqualIfAtLeastVersion(self, source, version_tuple, version2=None):
+        if version2 is None:
+            version2 = version_tuple[0], version_tuple[1] - 1
         if sys.version_info >= version_tuple:
             self.assertAstSourceEqual(source)
-        else:
+        elif sys.version_info <= version2:
             self.assertRaises(SyntaxError, ast.parse, source)
 
     def test_imports(self):
@@ -36,6 +38,8 @@ class CodegenTestCase(unittest.TestCase):
         self.assertAstSourceEqual(source)
         source = "from math import floor"
         self.assertAstSourceEqual(source)
+        source = "from .. import foobar"
+        self.assertAstSourceEqual(source)
 
     def test_dictionary_literals(self):
         source = "{'a': 1, 'b': 2}"
@@ -58,6 +62,20 @@ class CodegenTestCase(unittest.TestCase):
             sys.stdout.write(exc)""")
         self.assertAstSourceEqual(source)
 
+        source = textwrap.dedent("""\
+        try:
+            'spam'[10]
+        except IndexError as exc:
+            sys.stdout.write(exc)
+        else:
+            pass
+        finally:
+            pass""")
+        # This is interesting -- the latest 2.7 compiler seems to
+        # handle this OK, but creates an AST with nested try/finally
+        # and try/except, so the source code doesn't match.
+        self.assertAstSourceEqualIfAtLeastVersion(source, (3, 4), (1, 0))
+
     def test_del_statement(self):
         source = "del l[0]"
         self.assertAstSourceEqual(source)
@@ -82,6 +100,11 @@ class CodegenTestCase(unittest.TestCase):
                           if isinstance(n, ast.arguments)][0]
         self.assertEqual(astor.to_source(arguments_node),
                          "a1, a2, b1=j, b2='123', b3={}, b4=[]")
+        source = textwrap.dedent("""\
+        def call(*popenargs, timeout=None, **kwargs):
+            pass""")
+        # Probably also works on < 3.4, but doesn't work on 2.7...
+        self.assertAstSourceEqualIfAtLeastVersion(source, (3, 4), (2, 7))
 
     def test_matrix_multiplication(self):
         for source in ("(a @ b)", "a @= b"):
@@ -113,6 +136,19 @@ class CodegenTestCase(unittest.TestCase):
             pass""")
         self.assertAstSourceEqualIfAtLeastVersion(source, (3, 0))
 
+    def test_yield(self):
+        source = "yield"
+        self.assertAstSourceEqual(source)
+        source = textwrap.dedent("""\
+        def dummy():
+            yield""")
+        self.assertAstSourceEqual(source)
+        source = "foo((yield bar))"
+        self.assertAstSourceEqual(source)
+        source = "return (yield from sam())"
+        # Probably also works on < 3.4, but doesn't work on 2.7...
+        self.assertAstSourceEqualIfAtLeastVersion(source, (3, 4), (2, 7))
+
 
 if __name__ == '__main__':
     unittest.main()