From 165eda57336afd2fcc205a07bed662e021c81861 Mon Sep 17 00:00:00 2001
From: Chris Withers <chris@simplistix.co.uk>
Date: Tue, 23 Feb 2010 17:17:08 +0000
Subject: a handy @classproperty decorator

---
 lib/sqlalchemy/util.py | 10 ++++++++++
 1 file changed, 10 insertions(+)

(limited to 'lib/sqlalchemy/util.py')

diff --git a/lib/sqlalchemy/util.py b/lib/sqlalchemy/util.py
index 873243de1..97270004b 100644
--- a/lib/sqlalchemy/util.py
+++ b/lib/sqlalchemy/util.py
@@ -1639,3 +1639,13 @@ def _decorate_with_warning(func, wtype, message, docstring_header=None):
     decorated = warned(func)
     decorated.__doc__ = doc
     return decorated
+
+class classproperty(property):
+    """A decorator that behaves like @property except that operates
+    on classes rather than instances.
+
+    This is helpful when you need to compute __table_args__ and/or
+    __mapper_args__ when using declarative."""
+    def __get__(desc, self, cls):
+        return desc.fget(cls)
+
-- 
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