Add force_auto_coercion

docs/coercion.rst

@@ -4,35 +4,7 @@ Using automatic data coercion
 SQLAlchemy-Utils provides various new data types for SQLAlchemy and in order to gain full
 advantage of these datatypes you should use coercion_listener. Setting up the listener is easy:
 
-::
 
-    import sqlalchemy as sa
+.. module:: sqlalchemy_utils.listeners
-    from sqlalchemy_utils import coercion_listener
 
-
+.. autofunction:: force_auto_coercion
-    sa.event.listen(sa.orm.mapper, 'mapper_configured', coercion_listener)
-
-
-The listener automatically detects SQLAlchemy-Utils compatible data types and coerces all attributes
-using these types to appropriate objects.
-
-
-Example
-::
-
-
-    from colour import Color
-    from sqlalchemy_utils import ColorType
-
-
-    class Document(Base):
-        __tablename__ = 'document'
-        id = sa.Column(sa.Integer, autoincrement=True)
-        name = sa.Column(sa.Unicode(50))
-        background_color = sa.Column(ColorType)
-
-
-    document = Document()
-    document.background_color = 'F5F5F5'
-    document.background_color  # Color object
-    session.commit()

sqlalchemy_utils/listeners.py

@@ -28,7 +28,45 @@ def instant_defaults_listener(target, args, kwargs):
                 setattr(target, key, column.default.arg)
 
 
-def coerce_data_types(mapper=sa.orm.mapper):
+def force_auto_coercion(mapper=sa.orm.mapper):
+    """
+    Function that assigns automatic data type coercion for all classes which
+    are of type of given mapper. The coercion is applied to all coercion
+    capable properties. By default coercion is applied to all SQLAlchemy
+    mappers.
+
+    Before initializing your models you need to call force_auto_coercion.
+
+    ::
+
+        from sqlalchemy_utils import force_auto_coercion
+
+
+        force_auto_coercion()
+
+
+    Then define your models the usual way::
+
+
+        class Document(Base):
+            __tablename__ = 'document'
+            id = sa.Column(sa.Integer, autoincrement=True)
+            name = sa.Column(sa.Unicode(50))
+            background_color = sa.Column(ColorType)
+
+
+    Now scalar values for coercion capable data types will convert to
+    appropriate value objects::
+
+        document = Document()
+        document.background_color = 'F5F5F5'
+        document.background_color  # Color object
+        session.commit()
+
+
+    :param mapper: The mapper which the automatic data type coercion should be
+                   applied to
+    """
     sa.event.listen(mapper, 'mapper_configured', coercion_listener)