The Zen of Zope, by Jeffrey 'Alex' Clark

A crash course on the Zope Component Architecture (ZCA), told through the 19 aphorisms of The Zen of Python.

Background

Python has import this, which prints The Zen of Python by Tim Peters. Daniel Greenfeld answered it with that, The Anti-Zen of Python. And so, naturally, there is import other.

Each line of the Zen is rewritten around a ZCA concept and then demonstrated with working zope.interface and zope.component code: interfaces and the objects that implement or provide them, invariants, tagged values, adapters and multi-adapters, subscribers, adapter hooks, verification and utilities. Read src/other/__init__.py in the repository from top to bottom to see how each line is produced.

It was written in 2012, based on the zope.interface and zope.component documentation, and updated for Python 3 in 2026.

Installation

other requires Python 3.10 or later. Install it from PyPI:

$ pip install other

This also installs zope.component and zope.interface.

Usage

Run it from the command line (import other prints the same thing):

$ python -m other
The Zen of Zope, by Jeffrey 'Alex' Clark


Beautiful is an attribute of person.
Explicit is implemented by implicit.
Simple is provided by complex.
Complex is directly provided by complicated.
Flat only implements nested.
Sparse has tagged value dense.
Readability count is not in range.
Special cases could not adapt the rules.
Practicality implements purity.
Errors should never require a specification that doesn’t extend the specification of silence.
Unless explicit is a multi-adapter.
In subscribing to ambiguity, return all the objects that refuse the temptation to guess.
There should be none-- and preferably only zero --output from a handler.
Although that way may not be obvious at first unless you've registered an adapter hook.
Now is verified by never.
Although never is not implemented by *right* now.
If the implementation is hard to explain, it queries the bad idea utility.
If the implementation is easy to explain, it may query the good idea utility.
Implicit namespace packages are one honking great idea -- let's do more of those!

Development

Clone the repository and install it in editable mode, along with the dev dependency group (pip 25.1 or later):

$ git clone https://github.com/aclark4life/other.git
$ cd other
$ pip install -e . --group dev

Run the tests with pytest from the root of the clone:

$ pytest

Linting and formatting use ruff, run through prek pre-commit hooks. Install the hooks once per clone, and they run on every commit:

$ prek install

To run every hook against every file (this may fix and reformat files):

$ prek run --all-files

License

MIT. See LICENSE.

Changelog

2.1.0 (2026/10/23)

• Declare zope.interface as a direct dependency [aclark]
• Add a dev dependency group with prek [aclark]
• License under MIT [aclark]
• Drop the that dependency; it was never imported [aclark]
• Use the full author name, Jeffrey 'Alex' Clark [aclark]
• Convert the README to Markdown and rename CHANGES.txt to CHANGELOG.md [aclark]
• Run the tests with pytest; add a test dependency group [aclark]
• Make other a package in a src layout, with tests in tests/ [aclark]
• Reorganize the tutorial so each section defines what it uses [aclark]
• Trim boilerplate from the tutorial: dataclasses instead of assign-only __init__ methods, one-line docstrings, size() instead of getSize() [aclark]
• Explain in each section's banner how its line of the Zen becomes ZCA code [aclark]
• Make section 3 literally true: ISimple is provided by a Complex instance [aclark]
• Drop MANIFEST.in and requirements.txt; add Python version classifiers, keywords and project URLs [aclark]
• Add background, installation and development sections to the README [aclark]
• Fix the adapter hook breaking failed adaptation process-wide after import [aclark]
• Make sections 1, 10, 11 and 13 demonstrate what their lines describe [aclark]
• Test the full output against the README, and the adapter hook fix [aclark]

2.0.1 (2026/10/22)

• Replace Gittip URL with GitHub Sponsors Funding URL in project metadata [aclark]

2.0.0 (2026/10/22)

• Drop Python 2; require Python 3.10+ [aclark]
• Use @implementer class decorators instead of implements() [aclark]
• Move packaging to pyproject.toml [aclark]
• Publish to PyPI with trusted publishing via GitHub Actions [aclark]
• Add tests [aclark]

1.0.0 (2012/12/8)

• First release [aclark]