# HG changeset patch
# User mgood
# Date 1249850339 0
# Node ID 9cabfbc4ac5cf74ddfae8cbbc933c97b936d6edb
# Parent  0af77f663a6511ee4af8a95c7a5baf076ac50590
Fix nested list comprehensions & generator expressions (fixes #327)

diff --git a/genshi/template/eval.py b/genshi/template/eval.py
--- a/genshi/template/eval.py
+++ b/genshi/template/eval.py
@@ -558,15 +558,13 @@
     # GeneratorExp(expr elt, comprehension* generators)
     def visit_GeneratorExp(self, node):
         gens = []
-        # need to visit them in inverse order
-        for generator in node.generators[::-1]:
+        for generator in node.generators:
             # comprehension = (expr target, expr iter, expr* ifs)
             self.locals.append(set())
             gen = _new(_ast.comprehension, self.visit(generator.target),
-                            self.visit(generator.iter),
-                            [self.visit(if_) for if_ in generator.ifs])
+                       self.visit(generator.iter),
+                       [self.visit(if_) for if_ in generator.ifs])
             gens.append(gen)
-        gens.reverse()
 
         # use node.__class__ to make it reusable as ListComp
         ret = _new(node.__class__, self.visit(node.elt), gens)
diff --git a/genshi/template/tests/eval.py b/genshi/template/tests/eval.py
--- a/genshi/template/tests/eval.py
+++ b/genshi/template/tests/eval.py
@@ -258,6 +258,14 @@
         self.assertEqual([2, 3, 4, 5, 6],
                          expr.evaluate({'numbers': range(5), 'offset': 2}))
 
+        expr = Expression("[n for group in groups for n in group]")
+        self.assertEqual([0, 1, 0, 1, 2],
+                         expr.evaluate({'groups': [range(2), range(3)]}))
+
+        expr = Expression("[(a, b) for a in x for b in y]")
+        self.assertEqual([('x0', 'y0'), ('x0', 'y1'), ('x1', 'y0'), ('x1', 'y1')],
+                         expr.evaluate({'x': ['x0', 'x1'], 'y': ['y0', 'y1']}))
+
     def test_list_comprehension_with_getattr(self):
         items = [{'name': 'a', 'value': 1}, {'name': 'b', 'value': 2}]
         expr = Expression("[i.name for i in items if i.value > 1]")
@@ -280,6 +288,14 @@
         self.assertEqual([2, 3, 4, 5, 6],
                          expr.evaluate({'numbers': range(5), 'offset': 2}))
 
+        expr = Expression("list(n for group in groups for n in group)")
+        self.assertEqual([0, 1, 0, 1, 2],
+                         expr.evaluate({'groups': [range(2), range(3)]}))
+
+        expr = Expression("list((a, b) for a in x for b in y)")
+        self.assertEqual([('x0', 'y0'), ('x0', 'y1'), ('x1', 'y0'), ('x1', 'y1')],
+                         expr.evaluate({'x': ['x0', 'x1'], 'y': ['y0', 'y1']}))
+
     def test_generator_expression_with_getattr(self):
         items = [{'name': 'a', 'value': 1}, {'name': 'b', 'value': 2}]
         expr = Expression("list(i.name for i in items if i.value > 1)")