prototype

id	creational/prototype
name	Prototype
aliases	clone
guide_url	https://python-patterns.guide/gang-of-four/prototype/
problem	Create new objects by copying a pre-configured exemplar instead of constructing from scratch.
symptoms	expensive construction objects that start from a template registry of preconfigured instances clone this object
verdict	prefer-alternative
caveats	The pattern targets a 1990s problem: languages where classes weren't first-class values. In Python you just pass the class, or a functools.partial, or a bound copy call. If you do copy, know your depth: copy.copy shares nested mutable state; copy.deepcopy does not.
stdlib_sightings	copy.copy copy.deepcopy functools.partial

Prototype

Stamp out new objects from named, pre-configured starting points. Verdict: prefer an alternative — store callables (functools.partial), not exemplars with a clone() protocol; tweak frozen products with dataclasses.replace.

Where	What
pattern/	The importable code: TemplateRegistry, Template
docs/	Fundamentals · Implementation guide · External examples
examples/report_job_templates/	Mini-project: a report scheduler stamping jobs from a template menu
tests/	Behavioral tests for the pattern and the mini-project

uv run python -m patterns.creational.prototype.examples.report_job_templates.main