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Fixed #15570 -- Corrected a flaw in the design of the silent flag on …

…{% cycle %}. Thanks to Brian Neal for the report, and to Andrew and Jannis for the design consult.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@15773 bcc190cf-cafb-0310-a4f2-bffc1f526a37
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commit c260c533e1f1553548fc98f24820805af87f72bf 1 parent 32adde7
@freakboy3742 freakboy3742 authored
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4 django/template/defaulttags.py
@@ -111,12 +111,12 @@ def render(self, context):
if self not in context.render_context:
# First time the node is rendered in template
context.render_context[self] = itertools_cycle(self.cyclevars)
- if self.silent:
- return ''
cycle_iter = context.render_context[self]
value = cycle_iter.next().resolve(context)
if self.variable_name:
context[self.variable_name] = value
+ if self.silent:
+ return ''
return value
class DebugNode(Node):
View
51 docs/ref/templates/builtins.txt
@@ -102,11 +102,31 @@ outside of a loop. To do this, just give the ``{% cycle %}`` tag a name, using
{% cycle 'row1' 'row2' as rowcolors %}
-From then on, you can insert the current value of the cycle wherever you'd like
-in your template::
-
- <tr class="{% cycle rowcolors %}">...</tr>
- <tr class="{% cycle rowcolors %}">...</tr>
+From then on, you can insert the current value of the cycle wherever
+you'd like in your template by referencing the cycle name as a context
+variable. If you want to move the cycle onto the next value, you use
+the cycle tag again, using the name of the variable. So, the following
+template::
+
+ <tr>
+ <td class="{% cycle 'row1' 'row2' as rowcolors %}">...</td>
+ <td class="{{ rowcolors }}">...</td>
+ </tr>
+ <tr>
+ <td class="{% cycle rowcolors %}">...</td>
+ <td class="{{ rowcolors }}">...</td>
+ </tr>
+
+would output::
+
+ <tr>
+ <td class="row1">...</td>
+ <td class="row1">...</td>
+ </tr>
+ <tr>
+ <td class="row2">...</td>
+ <td class="row2">...</td>
+ </tr>
You can use any number of values in a ``{% cycle %}`` tag, separated by spaces.
Values enclosed in single (``'``) or double quotes (``"``) are treated as
@@ -144,16 +164,25 @@ use the value in a nested loop or an included template. If you want to
just declare the cycle, but not output the first value, you can add a
``silent`` keyword as the last keyword in the tag. For example::
- {% cycle 'row1' 'row2' as rowcolors silent %}
{% for obj in some_list %}
- <tr class="{% cycle rowcolors %}">{{ obj }}</tr>
+ {% cycle 'row1' 'row2' as rowcolors silent %}
+ <tr class="{{ rowcolors }}">{% include "subtemplate.html " %}</tr>
{% endfor %}
This will output a list of ``<tr>`` elements with ``class``
-alternating between ``row1`` and ``row2``. If the ``silent`` keyword
-were to be omitted, ``row1`` would be emitted as normal text, outside
-the list of ``<tr>`` elements, and the first ``<tr>`` would have a
-class of ``row2``.
+alternating between ``row1`` and ``row2``; the subtemplate will have
+access to ``rowcolors`` in it's context that matches the class of the
+``<tr>`` that encloses it. If the ``silent`` keyword were to be
+omitted, ``row1`` would be emitted as normal text, outside the
+``<tr>`` element.
+
+When the silent keyword is used on a cycle definition, the silence
+automatically applies to all subsequent uses of the cycle tag. In,
+the following template would output *nothing*, even though the second
+call to ``{% cycle %}`` doesn't specify silent::
+
+ {% cycle 'row1' 'row2' as rowcolors silent %}
+ {% cycle rowcolors %}
.. templatetag:: debug
View
6 tests/regressiontests/templates/tests.py
@@ -735,11 +735,15 @@ def get_template_tests(self):
'cycle14': ("{% cycle one two as foo %}{% cycle foo %}", {'one': '1','two': '2'}, '12'),
'cycle15': ("{% for i in test %}{% cycle aye bee %}{{ i }},{% endfor %}", {'test': range(5), 'aye': 'a', 'bee': 'b'}, 'a0,b1,a2,b3,a4,'),
'cycle16': ("{% cycle one|lower two as foo %}{% cycle foo %}", {'one': 'A','two': '2'}, 'a2'),
- 'cycle17': ("{% cycle 'a' 'b' 'c' as abc silent %}{% cycle abc %}{% cycle abc %}{% cycle abc %}{% cycle abc %}", {}, "abca"),
+ 'cycle17': ("{% cycle 'a' 'b' 'c' as abc silent %}{% cycle abc %}{% cycle abc %}{% cycle abc %}{% cycle abc %}", {}, ""),
'cycle18': ("{% cycle 'a' 'b' 'c' as foo invalid_flag %}", {}, template.TemplateSyntaxError),
'cycle19': ("{% cycle 'a' 'b' as silent %}{% cycle silent %}", {}, "ab"),
'cycle20': ("{% cycle one two as foo %} &amp; {% cycle foo %}", {'one' : 'A & B', 'two' : 'C & D'}, "A & B &amp; C & D"),
'cycle21': ("{% filter force_escape %}{% cycle one two as foo %} & {% cycle foo %}{% endfilter %}", {'one' : 'A & B', 'two' : 'C & D'}, "A &amp; B &amp; C &amp; D"),
+ 'cycle22': ("{% for x in values %}{% cycle 'a' 'b' 'c' as abc silent %}{{ x }}{% endfor %}", {'values': [1,2,3,4]}, "1234"),
+ 'cycle23': ("{% for x in values %}{% cycle 'a' 'b' 'c' as abc silent %}{{ abc }}{{ x }}{% endfor %}", {'values': [1,2,3,4]}, "a1b2c3a4"),
+ 'included-cycle': ('{{ abc }}', {'abc': 'xxx'}, 'xxx'),
+ 'cycle24': ("{% for x in values %}{% cycle 'a' 'b' 'c' as abc silent %}{% include 'included-cycle' %}{% endfor %}", {'values': [1,2,3,4]}, "abca"),
### EXCEPTIONS ############################################################
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