defaultable 0.1.1

A simple Python package for defaultable abstract base classes

🧩 Defaultable

Defaultable is a lightweight Python package that provides abstract base classes for defining "default" instances in your own classes — useful for fallbacks, comparisons, initialization patterns, or clean APIs.

It supports both:

• ✅ Public default behavior via Defaultable
• 🔒 Internal default behavior via InternalDefaultable

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🚀 Installation

Install the package from PyPI:

pip install defaultable

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📦 Usage Examples

🔹 Public: Using Defaultable

Use the Defaultable base class when you want to expose a public default instance for your class.

from defaultable import Defaultable
 
class ComplexNumber(Defaultable):
    def __init__(self, re: float, im: float):
        self.re = re
        self.im = im
 
    @classmethod
    def default(cls):
        return cls(1.0, 0.0)  # Default is 1 + 0j
 
    def __eq__(self, other):
        return isinstance(other, ComplexNumber) and self.re == other.re and self.im == other.im
 
    def __repr__(self):
        return f"({self.re} + {self.im}j)

Usage:

>>> c = ComplexNumber.default()
>>> print(c)
(1.0 + 0.0j)
 
>>> ComplexNumber.is_default(c)
True

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🔸 Internal: Using InternalDefaultable

Use the InternalDefaultable base class when you need internal logic for a default instance, without exposing it to the public API.

from defaultable import InternalDefaultable
 
class Complex(InternalDefaultable):
    def __init__(self, re: float, im: float):
        self.re = re
        self.im = im
 
    @classmethod
    def _default(cls):
        return cls(0.0, 0.0)  # Internal default is 0 + 0j
 
    def __bool__(self):
        default_complex = self._default()
        return self.im != default_complex.im or self.re != default_complex.re

Internal usage:

>>> my_complex = Complex(0, 0)
>>> bool(my_complex)
False

🔒 InternalDefaultable is designed for internal/private use. Its methods are prefixed with underscores and should not be exposed in public APIs.

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📄 License

This project is licensed under the MIT License.

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🛠️ Contributing

Contributions are welcome! Feel free to open issues or pull requests on GitHub.

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🔗 Links

• PyPI Package
• GitHub Repository