By default to_yaml_dict returns vars(self) and from_yaml_dict returns cls(**dct). Fixes #1

Author: smarie

yamlable/base.py

@@ -17,19 +17,21 @@ class AbstractYamlObject(ABC):
     Adds convenient methods load(s)_yaml/dump(s)_yaml to any object, to call pyyaml features directly on the object or
     on the object class.
 
-    Also adds the two abstract methods to_yaml_dict / from_yaml_dict, that are common to YamlObject2 and YamlAble
+    Also adds the two methods to_yaml_dict / from_yaml_dict, that are common to YamlObject2 and YamlAble.
+    Default implementation uses vars(self) and cls(**dct), but subclasses can override.
     """
 
-    @abstractmethod
     def to_yaml_dict(self) -> Dict[str, Any]:
         """
         Implementors should transform the object into a dictionary containing all information necessary to decode the
         object in the future. That dictionary will be serialized as a YAML mapping.
+
+        Default implementation returns vars(self)
         :return:
         """
+        return vars(self)
 
     @classmethod
-    @abstractmethod
     def from_yaml_dict(cls: 'Type[Y]', dct: Dict[Any, Any], yaml_tag: str) -> Y:
         """
         Implementors should transform the given dictionary (read from yaml by the pyYaml stack) into an object instance.
@@ -38,11 +40,14 @@ def from_yaml_dict(cls: 'Type[Y]', dct: Dict[Any, Any], yaml_tag: str) -> Y:
         Note that for YamlAble and YamlObject2 subclasses, if this method is called the yaml tag will already have
         been checked so implementors do not have to validate it.
 
+        Default implementation returns cls(**dct)
+
         :param dct:
         :param yaml_tag: the yaml schema id that was used for encoding the object (it has already been checked
             against is_json_schema_id_supported)
         :return:
         """
+        return cls(**dct)
 
     def dump_yaml(self, file_path_or_stream: Union[str, TextIOBase], **pyyaml_kwargs):
         """

yamlable/tests/test_yamlable.py

@@ -96,3 +96,19 @@ def is_yaml_tag_supported(cls, yaml_tag: str):
         Foo_Err.loads_yaml("!yamlable/yaml.tests.Foo_Err {a: 1, b: hello}\n")
 
     assert "No YamlAble subclass found able to decode object" in str(err_info.value)
+
+
+def test_yamlable_default_impl():
+    """ tests that the default implementation works """
+
+    @yaml_info(yaml_tag_ns='yaml.tests')
+    class Foo_Default(YamlAble):
+        def __init__(self, a, b):
+            self.a = a
+            self.b = b
+
+    f = Foo_Default(1, 'hello')
+    s = '!yamlable/yaml.tests.Foo_Default {a: 1, b: hello}\n'
+    assert dump(f) == s
+
+    assert dump(load(dump(load(s)))) == s