examples

Examples

Every program here runs with uv run poop <path>. POOP ships 44 programs across three subfolders, grouped by what they teach.

Language basics (basics/)

• hello_world.py — the smallest POOP program
• greet.py — string input + concatenation
• fizzbuzz.py — control flow via if_true_if_false
• leap_year.py — and_ / or_ / not_
• collatz.py — while-style recursion
• grades.py — collection processing
• string_iteration.py — a string is a collection too
• slicing.py — Slice as a reusable value object
• bank_account.py — encapsulation

Idiomatic POOP (idiomatic/)

• pipeline.py — filter / filter_false / map / do chain
• safe_config.py — if_none / if_not_none cascade
• common_interests.py — set operations
• statistics.py — number aggregation
• rpn_calculator.py — stack as a POOP List
• roman_numerals.py — string mapping
• managed_resource.py — With and the __exit__ protocol

Classic OO patterns (Sandi Metz / GoF) (patterns/)

Creational

• abstract_factory.py — Abstract Factory
• builder.py — Builder
• factory_method.py — Factory Method
• prototype.py — Prototype (cloning a configured example)
• singleton.py — Singleton (class-side cached instance)

Structural

• adapter.py — Adapter
• bridge.py — Bridge
• tree.py — Composite (replacing isinstance)
• decorators.py — Decorator (composition by delegation)
• facade.py — Facade
• flyweight.py — Flyweight (shared intrinsic state)
• proxy.py — Proxy (lazy-loading virtual proxy)

Behavioral

• chain_of_responsibility.py — Chain of Responsibility
• command.py — Command (with undo)
• interpreter.py — Interpreter
• iterator.py — Iterator
• mediator.py — Mediator
• memento.py — Memento
• observer.py — Observer
• door.py — State
• discounts.py — Strategy
• template_method.py — Template Method
• visitor.py — Visitor

Other OO patterns (Fowler / Beck / Evans / Metz)

• null_customer.py — Null Object
• payroll.py — polymorphism replacing if employee.type == ...
• specification.py — Specification (composable rules replacing and/or/not)
• money.py — Money value object
• execute_around.py — Execute Around Method