Adding render_template template tag.

It's just like an include tag but instead of pointing to a direct *.html
file you point to a directory and the filename is derived from the
object's content type.

basic/tools/templatetags/objectutils.py

@@ -0,0 +1,50 @@
+from django import template
+from django.template.loader import render_to_string
+from django.template.defaultfilters import slugify
+
+from basic.tools.templatetags.utils import parse_ttag
+
+register = template.Library()
+
+
+class RenderTemplateNode(template.Node):
+    def __init__(self, object_name, template_dir):
+        self.object_name = object_name
+        self.template_dir = template_dir.rstrip('/').strip('"').strip("'")
+
+    def render(self, context):
+        try:
+            obj = template.resolve_variable(self.object_name, context)
+            template_name = '%s.%s.html' % (obj._meta.app_label, obj._meta.module_name)
+            template_list = [
+                '%s/%s' % (self.template_dir, template_name),
+                '%s/default.html' % self.template_dir
+            ]
+            context['object'] = obj
+            return render_to_string(template_list, context)
+        except AttributeError:
+            if (type(obj) in (int, unicode, str)):
+                return obj
+            return ''
+        except template.VariableDoesNotExist:
+            return ''
+
+
+@register.tag()
+def render_template(parser, token):
+    """
+    Returns the proper template based on the objects content_type. If an
+    template doesn't exist it'll fallback to default.html.
+
+    Syntax:
+
+        {% render_template for [object] in [path to templates] %}
+
+    Usage:
+
+        {% render_template for entry in "includes/lists" %}
+    """
+    tags = parse_ttag(token, ['for', 'in'])
+    if len(tags) != 3:
+        raise template.TemplateSyntaxError, '%r tag has invalid arguments' % tags['tag_name']
+    return RenderTemplateNode(object_name=tags['for'], template_dir=tags['in'])