Ticket #5172: simple-for.patch

django/template/defaulttags.py

@@ -79 +79 @@
             reversed = ' reversed'
         else:
             reversed = ''
-        return "<For Node: for %s in %s, tail_len: %d%s>" % \
-            (', '.join( self.loopvars ), self.sequence, len(self.nodelist_loop), reversed)
+        loopvars = loopvars and '%s in ' % ', '.join(self.loopvars) or '' 
+        return "<For Node: for %s%s, length of: %d%s>" % (loopvars,
+                 self.sequence, len(self.nodelist_loop), reversed)
 
     def __iter__(self):
         for node in self.nodelist_loop:
@@ -106 +107 @@
             values = []
         if values is None:
             values = []
+        if not self.loopvars:
+            # It's a simple integer-based loop
+            try:
+                values = range(int(values))
+            except (ValueError, TypeError):
+                values = []
         if not hasattr(values, '__len__'):
             values = list(values)
         len_values = len(values)
@@ -128 +135 @@
             if unpack:
                 # If there are multiple loop variables, unpack the item into them.
                 context.update(dict(zip(self.loopvars, item)))
-            else:
+            elif self.loopvars:
                 context[self.loopvars[0]] = item
             for node in self.nodelist_loop:
                 nodelist.append(node.render(context))
@@ -567 +574 @@
                                     current one
         ==========================  ================================================
 
+    You can also set up a simple integer loop by passing in just an integer.
+    Nothing will be added to the context except for the ``forloop`` variable.
+
+        {% for 5 %}
+            loop: {{ forloop.counter }}
+        {% endfor %}
+        {% for my_integer %}
+            loop: {{ forloop.counter }}
+        {% endfor %}
     """
     bits = token.contents.split()
-    if len(bits) < 4:
-        raise TemplateSyntaxError, "'for' statements should have at least four words: %s" % token.contents
+    if len(bits) < 4 and len(bits) != 2:
+        raise TemplateSyntaxError, ("Invalid format for 'for' tag: %s" %
+                                    token.contents)
 
-    reversed = bits[-1] == 'reversed'
-    in_index = reversed and -3 or -2
-    if bits[in_index] != 'in':
-        raise TemplateSyntaxError, "'for' statements should use the format 'for x in y': %s" % token.contents
-
-    loopvars = re.sub(r' *, *', ',', ' '.join(bits[1:in_index])).split(',')
-    for var in loopvars:
-        if not var or ' ' in var:
-            raise TemplateSyntaxError, "'for' tag received an invalid argument: %s" % token.contents
-
-    sequence = parser.compile_filter(bits[in_index+1])
+    if len(bits) == 2:
+        reversed = False
+        loopvars = []
+        sequence = parser.compile_filter(bits[1])
+    else:
+        reversed = bits[-1] == 'reversed'
+        in_index = reversed and -3 or -2
+        if bits[in_index] != 'in':
+            raise TemplateSyntaxError, "'for' statements should use the format 'for x in y': %s" % token.contents
+    
+        loopvars = re.sub(r' *, *', ',', ' '.join(bits[1:in_index])).split(',')
+        for var in loopvars:
+            if not var or ' ' in var:
+                raise TemplateSyntaxError, "'for' tag received an invalid argument: %s" % token.contents
+    
+        sequence = parser.compile_filter(bits[in_index+1])
     nodelist_loop = parser.parse(('endfor',))
     parser.delete_first_token()
     return ForNode(loopvars, sequence, reversed, nodelist_loop)

docs/templates.txt

@@ -492 +492 @@
                                 current one
     ==========================  ================================================
 
+**New in Django development version**
+You can also set up a simple loop by passing just an integer variable (or
+constant)::
+
+    {% for var %}
+        loop: {{ forloop.counter }}
+    {% endfor %}
+
 if
 ~~
 

tests/regressiontests/templates/tests.py

@@ -356 +356 @@
             'for-tag-unpack11': ("{% for x,y,z in items %}{{ x }}:{{ y }},{{ z }}/{% endfor %}", {"items": (('one', 1), ('two', 2))}, ("one:1,/two:2,/", "one:1,INVALID/two:2,INVALID/")),
             'for-tag-unpack12': ("{% for x,y,z in items %}{{ x }}:{{ y }},{{ z }}/{% endfor %}", {"items": (('one', 1, 'carrot'), ('two', 2))}, ("one:1,carrot/two:2,/", "one:1,carrot/two:2,INVALID/")),
             'for-tag-unpack13': ("{% for x,y,z in items %}{{ x }}:{{ y }},{{ z }}/{% endfor %}", {"items": (('one', 1, 'carrot'), ('two', 2, 'cheese'))}, ("one:1,carrot/two:2,cheese/", "one:1,carrot/two:2,cheese/")),
+            'for-tag-simple01': ("{% for 5 %}{{ forloop.counter }},{% endfor %}", {}, "1,2,3,4,5,"),
+            'for-tag-simple02': ('{% for "5" %}{{ forloop.counter }},{% endfor %}', {}, "1,2,3,4,5,"),
+            'for-tag-simple03': ('{% for "not-a-number" %}{{ forloop.counter }},{% endfor %}', {}, ""),
+            'for-tag-simple04': ('{% for number %}{{ forloop.counter }},{% endfor %}', {'number': 5}, "1,2,3,4,5,"),
+            'for-tag-simple05': ('{% for number %}{{ forloop.counter }},{% endfor %}', {'number': '5'}, "1,2,3,4,5,"),
+            'for-tag-simple06': ('{% for number %}{{ forloop.counter }},{% endfor %}', {'number': 'not-a-number'}, ""),
+            'for-tag-simple07': ('{% for number %}{{ forloop.counter }},{% endfor %}', {}, ""),
 
             ### IF TAG ################################################################
             'if-tag01': ("{% if foo %}yes{% else %}no{% endif %}", {"foo": True}, "yes"),