From 3383e1ca375290d2cd248c11171ff7e5a2b92a4d Mon Sep 17 00:00:00 2001
From: Armin Ronacher <armin.ronacher@active-4.com>
Date: Mon, 24 Jan 2011 01:13:51 +0100
Subject: [PATCH] join now also accepts parameters

---
 CHANGES                     |  3 +++
 jinja2/filters.py           | 14 +++++++++++++-
 jinja2/nodes.py             |  1 +
 jinja2/runtime.py           |  1 -
 jinja2/testsuite/filters.py |  7 +++++++
 5 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/CHANGES b/CHANGES
index 7cda7b2..2cdedf4 100644
--- a/CHANGES
+++ b/CHANGES
@@ -29,6 +29,9 @@ Version 2.6
   optional starting index which defaultes to zero.  This now became the
   second argument to the function because it's rarely used.
 - like sum, sort now also makes it possible to order items by attribute.
+- like sum and sort, join now also is able to join attributes of objects
+  as string.
+- the internal eval context now has a reference to the environment.
 
 Version 2.5.5
 -------------
diff --git a/jinja2/filters.py b/jinja2/filters.py
index 8cd8387..fe33eb0 100644
--- a/jinja2/filters.py
+++ b/jinja2/filters.py
@@ -256,7 +256,7 @@ def do_default(value, default_value=u'', boolean=False):
 
 
 @evalcontextfilter
-def do_join(eval_ctx, value, d=u''):
+def do_join(eval_ctx, value, d=u'', attribute=None):
     """Return a string which is the concatenation of the strings in the
     sequence. The separator between elements is an empty string per
     default, you can define it with the optional parameter:
@@ -268,7 +268,19 @@ def do_join(eval_ctx, value, d=u''):
 
         {{ [1, 2, 3]|join }}
             -> 123
+
+    It is also possible to join certain attributes of an object:
+
+    .. sourcecode:: jinja
+
+        {{ users|join(', ', attribute='username') }}
+
+    .. versionadded:: 2.6
+       The `attribute` parameter was added.
     """
+    if attribute is not None:
+        value = imap(make_attrgetter(eval_ctx.environment, attribute), value)
+
     # no automatic escaping?  joining is a lot eaiser then
     if not eval_ctx.autoescape:
         return unicode(d).join(imap(unicode, value))
diff --git a/jinja2/nodes.py b/jinja2/nodes.py
index c18d299..f9da1da 100644
--- a/jinja2/nodes.py
+++ b/jinja2/nodes.py
@@ -77,6 +77,7 @@ class EvalContext(object):
     """
 
     def __init__(self, environment, template_name=None):
+        self.environment = environment
         if callable(environment.autoescape):
             self.autoescape = environment.autoescape(template_name)
         else:
diff --git a/jinja2/runtime.py b/jinja2/runtime.py
index 72ab93e..d73483d 100644
--- a/jinja2/runtime.py
+++ b/jinja2/runtime.py
@@ -8,7 +8,6 @@
     :copyright: (c) 2010 by the Jinja Team.
     :license: BSD.
 """
-import sys
 from itertools import chain, imap
 from jinja2.nodes import EvalContext, _context_function_types
 from jinja2.utils import Markup, partial, soft_unicode, escape, missing, \
diff --git a/jinja2/testsuite/filters.py b/jinja2/testsuite/filters.py
index 64cd0a9..ff04c9f 100644
--- a/jinja2/testsuite/filters.py
+++ b/jinja2/testsuite/filters.py
@@ -128,6 +128,13 @@ class FilterTestCase(JinjaTestCase):
         tmpl = env2.from_string('{{ ["<foo>", "<span>foo</span>"|safe]|join }}')
         assert tmpl.render() == '&lt;foo&gt;<span>foo</span>'
 
+    def test_join_attribute(self):
+        class User(object):
+            def __init__(self, username):
+                self.username = username
+        tmpl = env.from_string('''{{ users|join(', ', 'username') }}''')
+        assert tmpl.render(users=map(User, ['foo', 'bar'])) == 'foo, bar'
+
     def test_last(self):
         tmpl = env.from_string('''{{ foo|last }}''')
         out = tmpl.render(foo=range(10))
-- 
2.26.2