Fix issue #100

docs/switching.rst

@@ -177,9 +177,25 @@ operator.  Here are some examples::
 Loops
 ~~~~~
 
-For loops work very similar to Django, the only incompatibility is that in
-Jinja2 the special variable for the loop context is called `loop` and not
-`forloop` like in Django.
+For loops work very similar to Django. Notably, in Jinja2 the special variable for 
+the loop context is called `loop` and not `forloop` like in Django.
+
+In addition, the Django `empty` argument is called `else` in Jinja2. For example, the
+Django template::
+
+    {% for item in items %}
+        {{item}}
+    {% empty %}
+        No items!
+    {% endfor %}
+
+would be handled in Flask as::
+
+    {% for item in items %}
+        {{item}}
+    {% else %}
+        No items!
+    {% endfor %}
 
 Cycle
 ~~~~~

jinja2/compiler.py

@@ -1068,6 +1068,7 @@ def visit_For(self, node, frame):
         # make sure the loop variable is a special one and raise a template
         # assertion error if a loop tries to write to loop
         if extended_loop:
+            self.writeline('l_loop = None')
             loop_frame.identifiers.add_special('loop')
         for name in node.find_all(nodes.Name):
             if name.ctx == 'store' and name.name == 'loop':

jinja2/filters.py

@@ -176,7 +176,12 @@ def do_title(s):
     """Return a titlecased version of the value. I.e. words will start with
     uppercase letters, all remaining characters are lowercase.
     """
-    return soft_unicode(s).title()
+    rv = []
+    for item in re.compile(r'([-\s]+)(?u)').split(s):
+        if not item:
+            continue
+        rv.append(item[0].upper() + item[1:])
+    return ''.join(rv)
 
 
 def do_dictsort(value, case_sensitive=False, by='key'):

jinja2/parser.py

@@ -308,6 +308,8 @@ def parse_signature(self, node):
         while self.stream.current.type != 'rparen':
             if args:
                 self.stream.expect('comma')
+            if self.stream.current.type == 'rparen':
+                break
             arg = self.parse_assign_target(name_only=True)
             arg.set_ctx('param')
             if self.stream.skip_if('assign'):

jinja2/testsuite/core_tags.py

@@ -24,6 +24,10 @@ def test_simple(self):
         tmpl = env.from_string('{% for item in seq %}{{ item }}{% endfor %}')
         assert tmpl.render(seq=range(10)) == '0123456789'
 
+    def test_embedded_for_in_else(self):
+        tmpl = env.from_string('{% for item in seq %}{{ loop.index0 }}{% else %}{% for i in range(3) %}{{ i }}{% endfor %}{% endfor %}')
+        assert tmpl.render(seq=[]) == '012'
+
     def test_else(self):
         tmpl = env.from_string('{% for item in seq %}XXX{% else %}...{% endfor %}')
         assert tmpl.render() == '...'
@@ -222,6 +226,12 @@ def test_arguments(self):
 {{ m() }}|{{ m('a') }}|{{ m('a', 'b') }}|{{ m(1, 2, 3) }}''')
         assert tmpl.render() == '||c|d|a||c|d|a|b|c|d|1|2|3|d'
 
+    def test_trailing_comma(self):
+        tmpl = self.env.from_string('''\
+{% macro m(a, b,) %}{{ a }}|{{ b }}{% endmacro %}
+{{ m(1,2,) }}''')
+        assert tmpl.render() == '1|2'
+
     def test_varargs(self):
         tmpl = self.env.from_string('''\
 {% macro test() %}{{ varargs|join('|') }}{% endmacro %}\

jinja2/testsuite/filters.py

@@ -193,6 +193,16 @@ def test_string(self):
     def test_title(self):
         tmpl = env.from_string('''{{ "foo bar"|title }}''')
         assert tmpl.render() == "Foo Bar"
+        tmpl = env.from_string('''{{ "foo's bar"|title }}''')
+        assert tmpl.render() == "Foo's Bar"
+        tmpl = env.from_string('''{{ "foo   bar"|title }}''')
+        assert tmpl.render() == "Foo   Bar"
+        tmpl = env.from_string('''{{ "f bar f"|title }}''')
+        assert tmpl.render() == "F Bar F"
+        tmpl = env.from_string('''{{ "foo-bar"|title }}''')
+        assert tmpl.render() == "Foo-Bar"
+        tmpl = env.from_string('''{{ "foo\tbar"|title }}''')
+        assert tmpl.render() == "Foo\tBar"
 
     def test_truncate(self):
         tmpl = env.from_string(