Written-down changelog for the current development version

docs/changelog/changes_02.rst

@@ -1,4 +1,149 @@
 Changes in 0.2
 ==============
 
-TBD
+Backward-incompatible changes
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+- Changed type of :py:attr:`hiku.graph.Field.options` from
+  ``Mapping[str, Option]`` to ``Sequence[Option]``
+
+- Changed type of :py:attr:`hiku.graph.Link.options` from
+  ``Mapping[str, Option]`` to ``Sequence[Option]``
+
+- Changed type of :py:attr:`hiku.graph.Edge.fields` from
+  ``Mapping[str, Union[Field, Link]]`` to ``Sequence[Union[Field, Link]]``
+
+- Changed type of :py:attr:`hiku.query.Edge.fields` from
+  ``Mapping[str, Union[Field, Link]]`` to ``Sequence[Union[Field, Link]]``
+
+- :py:class:`hiku.graph.Graph` is not a subclass of the
+  :py:class:`hiku.graph.Edge` anymore, all the root edges,
+  fields and links should be defined in the :py:class:`hiku.graph.Root`
+  edge. Now :py:class:`hiku.graph.Graph` can contain only edges
+
+- All :py:mod:`hiku.types` and :py:mod:`hiku.typedef.types` are now
+  subclasses of ``type``, instead of being instances of ``type``
+
+- Renamed :py:class:`hiku.types.Type` into :py:class:`hiku.types.GenericMeta`
+- Renamed :py:class:`hiku.types.BooleanType` into :py:class:`hiku.types.Boolean`
+- Renamed :py:class:`hiku.types.StringType` into :py:class:`hiku.types.String`
+- Renamed :py:class:`hiku.types.IntegerType` into :py:class:`hiku.types.Integer`
+- Renamed :py:class:`hiku.types.OptionType` into :py:class:`hiku.types.Optional`
+- Renamed :py:class:`hiku.types.ListType` into :py:class:`hiku.types.Sequence`
+- Renamed :py:class:`hiku.types.DictType` into :py:class:`hiku.types.Mapping`
+- Renamed :py:class:`hiku.types.RecordType` into :py:class:`hiku.types.Record`
+- Renamed :py:class:`hiku.types.FunctionType` into :py:class:`hiku.types.Callable`
+- Removed :py:class:`hiku.types.ContainerType`
+- Removed :py:func:`hiku.types.to_instance`
+
+- Replaced required keyword argument ``to_list`` in the
+  :py:class:`hiku.graph.Link` with second positional argument, which
+  has a type of ``Union[Maybe, One, Many]``
+
+- Replaced required keyword argument ``to_list`` in the
+  :py:class:`hiku.sources.sqlalchemy.LinkQuery` with first positional
+  argument, which has a type of ``Union[Maybe, One, Many]``
+
+- Renamed required keyword argument and corresponding instance attribute
+  from ``doc`` into ``description`` in the :py:class:`hiku.graph.Field`,
+  :py:class:`hiku.graph.Link`, :py:class:`hiku.graph.Edge` and in the
+  :py:class:`hiku.sources.sqlalchemy.Link` classes
+
+- Renamed attribute of the :py:class:`hiku.typedef.kinko.TypeDoc`
+  from ``__type_doc__`` into ``__type_description__``
+
+- Moved constant :py:const:`hiku.engine.Nothing` to the
+  :py:const:`hiku.graph.Nothing`
+
+- Renamed attribute :py:attr:`hiku.result.Ref.storage` into
+  :py:attr:`hiku.result.Ref.index`
+
+- Renamed attribute :py:class:`hiku.result.State.idx` into
+  :py:class:`hiku.result.State.index`
+
+- :py:class:`hiku.sources.sqlalchemy.FieldsQuery` and
+  :py:class:`hiku.sources.sqlalchemy.LinkQuery` now require context
+  keys instead of "connectable" objects (SQLAlchemy's scoped session)
+
+- Moved type :py:class:`hiku.typedef.types.Unknown` to the
+  :py:class:`hiku.types.Unknown`
+
+New features
+~~~~~~~~~~~~
+
+- Added ability to export :py:mod:`hiku.query` nodes. Added
+  :py:mod:`hiku.export.simple` exporter, which will export query
+  into EDN data structure
+
+- Added debug mode for the :py:mod:`hiku.console` application,
+  showing Python tracebacks if debug mode is turned on
+
+- Implemented :py:class:`hiku.validate.query.QueryValidator`
+  to validate query against graph definition before it's execution
+
+- Implemented :py:class:`hiku.validate.graph.GraphValidator`
+  to validate graph definition
+
+- Added ability to define graph links with :py:const:`hiku.graph.Maybe`
+  type, this link will conform to the :py:class:`hiku.types.Optional` type
+  in the Hiku's type system:
+
+  .. code-block:: python
+
+    Link('link-to-foo', Maybe, func, edge='foo', requires=None)
+
+- Added ability to query complex fields, which has a type of
+  ``Optional[Record[...]]`` (Maybe), ``Record[...]`` (One) or
+  ``Sequence[Record[...]]`` (Many) as if they were linked edges:
+
+  .. code-block:: python
+
+    Edge('foo', [
+        Field('bar', Record[{'baz': Integer}], func),
+    ])
+
+  Here ``bar`` field should be queried as it was a link to the edge:
+
+  .. code-block:: clojure
+
+      [{:link-to-foo [{:bar [:baz]}]}]
+
+- Added ability to use scalar values in the expressions. Currently
+  only integer numbers and strings are supported:
+
+  .. code-block:: python
+
+    Expr('foo', foo_subgraph, func(S.this.foo, 'scalar'))
+
+- Implemented :py:func:`hiku.expr.if_some` function in order to unpack
+  :py:class:`hiku.types.Optional` type in expressions
+
+- Added ability to pass objects, required to execute query, using bound
+  to the query context:
+
+  .. code-block:: python
+
+    @pass_context
+    def func(ctx, fields):
+        return [ctx['storage'][f.name] for f in fields]
+
+    Root([
+        Field('foo', func),
+    ])
+
+    engine.execute(graph, read('[:foo]'),
+                   ctx={'storage': {'foo': 1}})
+
+- Implemented new :py:mod:`hiku.sources.aiopg` source for using aiopg_ and
+  :py:class:`hiku.executors.asyncio.AsyncIOExecutor` to asynchronously
+  load data from the `PostgreSQL` database
+
+- Added ability to define function arguments using types instead of queries:
+
+  .. code-block:: python
+
+    @define(Record[{'foo': Integer}])  # instead of @define('[[:foo]]')
+    def func(arg):
+        return arg['foo'] + 1
+
+.. _aiopg: http://aiopg.readthedocs.io/