implement base merging

kosokoso.py

@@ -8,10 +8,11 @@ import pprint
 import sys
 # import traceback
 
-Base = declarative_base()
+# this will get overridden by init_base
+Base = None
 
 
-class Tag(Base):
+class TagBase(object):
 
     def __eq__(self, other):
         return self.text == other.text
@@ -117,8 +118,7 @@ class Tag(Base):
                 return c
 
 
-
-class TagAssociation(Base):
+class TagAssociationBase(object):
     __tablename__ = "kk_tag_associations"
     db_id = sa.Column(sa.Integer, primary_key=True)
     tag_id = sa.Column(sa.Integer, sa.ForeignKey("kk_tags.db_id"))
@@ -131,7 +131,10 @@ class TagAssociation(Base):
     # m = sa.orm.mapper(Tag, Tag.__table__, non_primary=True,
     #         primary_key=[Tag.text])
     # tag_obj = sa.orm.relationship(m)
-    tag_obj = sa.orm.relationship(Tag)
+    @declared_attr
+    def tag_obj(self):
+        return sa.orm.relationship(Tag)
+    # tag_obj = sa.orm.relationship(Tag)
 
     # FIXME doesn't work, may not be needed.
     # tag_obj = sa.orm.relationship("Tag", back_populates="collection")
@@ -152,7 +155,8 @@ class TagAssociation(Base):
         return "tag assoc %s: %s:%s" % (self.db_id, 
                 self.target_table, self.target_id)
 
-class Taggable(Base):
+
+class TaggableBase(object):
     __abstract__ = True
 
     @declared_attr
@@ -197,6 +201,26 @@ class Taggable(Base):
                 )
 
 
+def init_base(new_base):
+    def init_cls(name, base):
+        current = globals()[name + 'Base']
+        new_ns = current.__dict__.copy()
+        del new_ns['__dict__']
+        new_ns = type(name, (new_base,), new_ns)
+        globals()[name] = new_ns
+
+    for c in ['Tag', 'TagAssociation', 'Taggable']:
+        init_cls(c, new_base)
+
+    globals()['Base'] = new_base
+    sa.event.listen(Tag, 'before_insert', delete_before_insert)
+    sa.event.listen(sa.orm.session.Session, 'before_flush',
+            enforce_unique_text)
+    return {'Tag': globals()['Tag'],
+            'TagAssociation': globals()['TagAssociation'],
+            'Taggable': globals()['Taggable']}
+
+
 def delete_before_insert(mapper, conn, target):
     # TODO figure out where exactly transactions happen.
     r = conn.execute("SELECT db_id FROM kk_tags WHERE text='%s'" %
@@ -214,6 +238,3 @@ def enforce_unique_text(session, flush_context, instances):
             if t:
                 i.db_id = t.db_id
 
-sa.event.listen(Tag, 'before_insert', delete_before_insert)
-sa.event.listen(sa.orm.session.Session, 'before_flush',
-        enforce_unique_text)

tests/test_basic.py

@@ -11,12 +11,11 @@ import unittest
 
 import libkosokoso as kk
 
-# TODO get this working -- merge bases?
-# DummyBase = sa.ext.declarative.declarative_base()
-class DummyBase(object):
-    """dummy"""
+DummyBase = sa.ext.declarative.declarative_base()
+kk.__dict__.update(kk.init_base(DummyBase))
 
-class Foo(DummyBase, kk.Taggable):
+# TODO make it so DummyBase doesn't have to come after the mixin.
+class Foo(kk.Taggable, DummyBase):
     __tablename__ = 'foos'
     db_id = sa.Column(sa.Integer, primary_key=True)
     def __repr__(self):
@@ -25,7 +24,7 @@ class Foo(DummyBase, kk.Taggable):
     def __eq__(self, other):
         return self.db_id == other.db_id
 
-class Bar(DummyBase, kk.Taggable):
+class Bar(kk.Taggable, DummyBase):
     __tablename__ = 'bars'
     db_id = sa.Column(sa.Integer, primary_key=True)
     def __repr__(self):
@@ -35,12 +34,15 @@ class ks_basic(unittest.TestCase):
     def setUp(self):
         # self.engine = sa.create_engine('sqlite://', echo=True)
         self.engine = sa.create_engine('sqlite://', echo=False)
-        kk.Base.metadata.create_all(self.engine)
+        DummyBase.metadata.create_all(self.engine)
         self.session = sa.orm.Session(self.engine)
 
     def tearDown(self):
         del self.engine
 
+    # def debug(self):
+    #     pprint.pprint(kk.__dict__)
+
     def test_add_as_object(self):
         a = Foo()
         self.session.add(a)
@@ -355,7 +357,7 @@ class ks_basic(unittest.TestCase):
         self.assertEqual(t3, kk.Tag('tag3'))
 
 
-    # TODO test concurrent setting the same tag from different
+    # TODO test concurrently setting the same tag from different
     # processes.
 
     # TODO delete unused tags