Fixed #3453: introduced a new template variable resolution system by Brian Harring (thanks!). The upshot is that variable resolution is about 25% faster, and you should see a measurable performance increase any time you've got long or deeply nested loops.

Variable resolution has changed behind the scenes -- see the note in templates_python.txt -- but template.resolve_variable() still exists. This should be fully backwards-compatible.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@6399 bcc190cf-cafb-0310-a4f2-bffc1f526a37

1 files changed, 30 insertions, 4 deletions

diff --git a/docs/templates_python.txt b/docs/templates_python.txt
index 232f54061f..b6173ad39a 100644
--- a/docs/templates_python.txt
+++ b/docs/templates_python.txt
@@ -928,10 +928,36 @@ current context, available in the ``render`` method::
 ``resolve_variable`` will try to resolve ``blog_entry.date_updated`` and then
 format it accordingly.
 
-.. note::
-    The ``resolve_variable()`` function will throw a ``VariableDoesNotExist``
-    exception if it cannot resolve the string passed to it in the current
-    context of the page.
+.. admonition:: New in development version:
+
+    Variable resolution has changed in the development version of Django.
+    ``template.resolve_variable()`` is still available, but has been deprecated
+    in favor of a new ``template.Variable`` class. Using this class will usually
+    be more efficient than calling ``template.resolve_variable``
+    
+    To use the ``Variable`` class, simply instantiate it with the name of the
+    variable to be resolved, and then call ``variable.resolve(context)``. So,
+    in the development version, the above example would be more correctly
+    written as:
+    
+    .. parsed-literal::
+    
+        class FormatTimeNode(template.Node):
+            def __init__(self, date_to_be_formatted, format_string):
+                self.date_to_be_formatted = **Variable(date_to_be_formatted)**
+                self.format_string = format_string
+        
+            def render(self, context):
+                try:
+                    actual_date = **self.date_to_be_formatted.resolve(context)**
+                    return actual_date.strftime(self.format_string)
+                except template.VariableDoesNotExist:
+                    return ''
+    
+    Changes are highlighted in bold.
+
+Variable resolution will throw a ``VariableDoesNotExist`` exception if it cannot
+resolve the string passed to it in the current context of the page.
 
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