Reviews notes

Jan 28 2020 - Session notes

• Question on SO: https://stackoverflow.com/questions/59904817/extending-wrapping-python-collections

projects that use "class Meta"

• Django's Model and Form definitions: https://docs.djangoproject.com/en/3.0/topics/db/models/ and https://docs.djangoproject.com/en/3.0/topics/forms/
• WTForm: https://wtforms.readthedocs.io/en/stable/, https://flask-wtf.readthedocs.io/en/stable/
• Marshmallow: https://marshmallow.readthedocs.io/en/stable/

Techniques

• https://docs.python.org/3/reference/datamodel.html#customizing-class-creation

Mapping adapter definitions

• Audience: Data scientist / data engineer

Mappings consist

Example

class FilenameMapper(Translator):
    def private(self, public, context):
        # filename -> full path
        return os.path.join(context.base, public)

    def public(self, private, context):
        return os.path.relative(...)


class MyKVStore(KVStore):
    class Meta:
        store = FilesystemStore("/path/to/something")
        keys = FilenameMapper()
        values = TextMapper(encoding="utf8")


print(MyKVStore)
# MyKVStore(store=<default>


class MoreComplex(KVStore):
    class Meta:
        store = ....
        keys = SpecialisedKeyValueTransformer(store)
        values = keys.valuetranformer()

---

Thor

def wrap_kvs(
  store, name, *,
  key_of_id=None, id_of_key=None, obj_of_data=None, data_of_obj=None, postget=None)

class MyStore(Store):
  def _id_of_key(self, k):
    return _id

Sep 25 2019 - Session notes

Projects:

• https://github.com/i2mint/py2store (https://pybay.com/speaker/thor-whalen/)
• https://github.com/thorwhalen/py2api
• https://github.com/thorwhalen/py2dash

Issues / subjects

• Sense of a feature not fitting with the architecture
• Pythonic API design?

links

Tools

• https://pre-commit.com/

  Example: https://github.com/psf/black/blob/master/.pre-commit-config.yaml

• black: https://github.com/psf/black

• flake8: http://flake8.pycqa.org/en/latest/

• example project using the above: https://github.com/mjpieters/collegial

Thor's scrap

  def __contains__(self, k) -> bool:
      return self.store.__contains__(self._id_of_key(k))