pep-484: the pep-484ening, SQL part three

hitting DML which is causing us to open up the
ColumnCollection structure a bit, as we do put anonymous
column expressions with None here.  However, we still want
Table /TableClause to have named column collections that
don't return None, so parametrize the "key" in this
collection also.

* rename some "immutable" elements to "readonly".  we change
  the contents of immutablecolumncollection underneath, so it's
  not "immutable"

Change-Id: I2593995a4e5c6eae874bed5bf76117198be8ae97

1 files changed, 11 insertions, 5 deletions

diff --git a/lib/sqlalchemy/cyextension/immutabledict.pyx b/lib/sqlalchemy/cyextension/immutabledict.pyx
index 861e7574d..6ab255311 100644
--- a/lib/sqlalchemy/cyextension/immutabledict.pyx
+++ b/lib/sqlalchemy/cyextension/immutabledict.pyx
@@ -1,18 +1,24 @@
 from cpython.dict cimport PyDict_New, PyDict_Update, PyDict_Size
 
 
+def _readonly_fn(obj):
+    raise TypeError(
+        "%s object is immutable and/or readonly" % obj.__class__.__name__)
+
+
 def _immutable_fn(obj):
-    raise TypeError("%s object is immutable" % obj.__class__.__name__)
+    raise TypeError(
+        "%s object is immutable" % obj.__class__.__name__)
 
 
-class ImmutableContainer:
+class ReadOnlyContainer:
 
     __slots__ = ()
 
-    def _immutable(self, *a,**kw):
-        _immutable_fn(self)
+    def _readonly(self, *a,**kw):
+        _readonly_fn(self)
 
-    __delitem__ = __setitem__ = __setattr__ = _immutable
+    __delitem__ = __setitem__ = __setattr__ = _readonly
 
 
 class ImmutableDictBase(dict):