[Zope-CVS] CVS: Packages/pypes/pypes - expression.py:1.18

[Casey Duncan]

Update of /cvs-repository/Packages/pypes/pypes
In directory cvs.zope.org:/tmp/cvs-serv16938

Modified Files:
	expression.py 
Log Message:
Add criteria and sort expressions for queries


=== Packages/pypes/pypes/expression.py 1.17 => 1.18 ===
--- Packages/pypes/pypes/expression.py:1.17	Tue May 11 23:58:40 2004
+++ Packages/pypes/pypes/expression.py	Thu Jul  1 23:14:21 2004
@@ -23,7 +23,7 @@
 from compiler import parse, ast, misc
 from compiler.pycodegen import ExpressionCodeGenerator, ModuleCodeGenerator
 from zope.interface import implements
-from pypes.interfaces import IExpression
+from pypes.interfaces import IExpression, IOrderExpression
 from pypes.exceptions import PypesError
 
 class Expression(object):
@@ -249,6 +249,8 @@
         combined if names common between them are assigned the same values
         and unbound names in one are not bound by the other.
         """
+        if self._bindings is other._bindings:
+            return self._bindings
         self_bound = Set(self._bindings)
         other_bound = Set(other._bindings)
         for name in other_bound & self_bound:
@@ -279,6 +281,33 @@
         return "Expression('%s')" % self._expr
     
     __repr__ = __str__
+
+
+class Criteria(Expression):
+    """Query criteria expression. Automatically binds names from the 
+    Python stack frame into the expression
+    """
+    
+    def __init__(self, expr, namespace=None):
+        frame_locals = sys._getframe(1).f_locals.copy()
+        if namespace is not None:
+            frame_locals.update(namespace)
+        super(Criteria, self).__init__(expr, frame_locals)
+
+
+class Asc(Criteria):
+    """Ascending order expression"""
+    
+    implements(IOrderExpression)        
+    order = 1
+
+
+class Desc(Criteria):
+    """Descendng order expression"""
+    
+    implements(IOrderExpression)        
+    order = -1
+
     
 def nodesEqual(node1, node2):
     """Return true if node1 and node2 are equivilant ast nodes. This is