patos 0.0.14

A flock of typed, zero-dependency Python design patterns. Each pattern is a single self-contained pato (a duck you adopt), fully typed, standard library only, and small enough to read in one sitting.

Install

pip install patos

Or copy a single duck. Open its docs page, copy the source from the Source section, and paste it into your own project. No dependency, no version pin, no tool, just one module you own.

The optional PostgreSQL toolkit installs SQLAlchemy, pgvector, and inflection only when a project asks for them.

pip install "patos[sql]"

from patos import sql

Patterns

Creational

Dispatch & selection

Structural & lifecycle

Command-line

Research registration

The seal covers the node's statement and the whole bytes of every other registered source. The statement starts at the first ## heading after the front matter and ends before the first ## Evidence, ## Ledger or ## Log heading, matched without regard to case. Front matter is never sealed, so status, date and the registration_sha256 field itself move freely, and a node that settles and appends to its log still verifies against the claim it was registered under. Every source is hashed as relative POSIX path \0 LF-normalized bytes \0, ordered by path, which keeps one seal identical on Windows and POSIX checkouts alike.

Optional extensions

Example

from patos import Singleton


class Settings(Singleton):
    def __init__(self) -> None:
        self.debug = False


a = Settings()
a.debug = True
b = Settings()      # same object, __init__ did not run again

assert a is b and b.debug

Documentation

Full documentation lives at phvv.me/patos.

Development

• Install: pip install -e ".[dev]"
• Lint: ruff check . && ruff format --check .
• Typecheck: pyrefly check
• Test: pytest
• Docs: pip install -e ".[docs]" && mkdocs build
• Build: python -m build