Changeset 382

Timestamp:

07/29/08 10:48:03 (4 years ago)

Author:

ged

Message:

- extra args and kwargs to Synonym and ColumnProperty are forwarded to their

underlying constructs

- fix ColumnProperty docstring

Location:

elixir/trunk

Files:

• CHANGES (modified) (1 diff)
• elixir/properties.py (modified) (8 diffs)

elixir/trunk/CHANGES

@@ -6 +6 @@
   resorting to using the ugly "column_kwargs" (patch from Jason R. Coombs,
   closes #39).
+- extra args and kwargs to Synonym and ColumnProperty are forwarded to their
+  underlying constructs
 
 

elixir/trunk/elixir/properties.py

@@ -67 +67 @@
     def create_properties(self):
         '''
-        Subclasses may override this method to add properties to the involved 
+        Subclasses may override this method to add properties to the involved
         entity.
         '''
@@ -128 +128 @@
 
         # delete the original attribute so that it doesn't interfere with
-        # SQLAlchemy.
+        # SQLAlchemy. Note that getattr and delattr are not symmetrical:
+        # getattr look up in parent classes, while delattr must be called on
+        # the exact class holding the attribute.
         if name in entity.__dict__:
             delattr(entity, name)
@@ -149 +151 @@
     '''
 
-    def __init__(self, prop):
-        super(GenericProperty, self).__init__()
+    def __init__(self, prop, *args, **kwargs):
+        super(GenericProperty, self).__init__(*args, **kwargs)
         self.prop = prop
+        self.args = args
+        self.kwargs = kwargs
 
     def create_properties(self):
@@ -162 +166 @@
 
     def evaluate_property(self, prop):
+        if self.args or self.kwargs:
+            raise Exception('superfluous arguments passed to GenericProperty')
         return prop
 
@@ -170 +176 @@
     ``column_property``'s.
 
-    It takes a single argument, which is a function (often
-    given as an anonymous lambda) taking one argument and returning the
-    desired (scalar-returning) SQLAlchemy ClauseElement. That function will be
-    called whenever the entity table is completely defined, and will be given
-    the .c attribute of the entity as argument (as a way to access the entity
-    columns). The ColumnProperty will first wrap your ClauseElement in a label
-    with the same name as the property, then wrap that in a column_property.
+    It takes a function (often given as an anonymous lambda) as its first
+    argument. Other arguments and keyword arguments are forwarded to the
+    column_property construct. That first-argument function must accept exactly
+    one argument and must return the desired (scalar-returning) SQLAlchemy
+    ClauseElement.
+
+    The function will be called whenever the entity table is completely
+    defined, and will be given
+    the .c attribute of the table of the entity as argument (as a way to
+    access the entity columns). The ColumnProperty will first wrap your
+    ClauseElement in an
+    "empty" label (ie it will be labelled automatically during queries),
+    then wrap that in a column_property.
 
     .. sourcecode:: python
@@ -183 +195 @@
             quantity = Field(Float)
             unit_price = Field(Numeric)
-            price = ColumnProperty(lambda c: c.quantity * c.unit_price)
+            price = ColumnProperty(lambda c: c.quantity * c.unit_price,
+                                   deferred=True)
 
     Please look at the `corresponding SQLAlchemy
@@ -191 +204 @@
 
     def evaluate_property(self, prop):
-        return column_property(prop.label(None))
+        return column_property(prop.label(None), *self.args, **self.kwargs)
 
 
@@ -216 +229 @@
 
     def evaluate_property(self, prop):
-        return synonym(prop)
+        return synonym(prop, *self.args, **self.kwargs)
 
 #class Composite(GenericProperty):