Result Handling Library

This library provides a robust mechanism for handling operations that can result in success (Ok) or failure (Err). Inspired by Rust's Result type, it aims to facilitate error handling in a more functional programming style in Python.

Features

• Result Type: Encapsulate successful outcomes with Ok and failures with Err.
• Comprehensive API: Methods for checking, transforming, and retrieving contained values or errors.
• Functional Programming Friendly: Supports map, map_err, and_then, and more to work with results without explicit error checking.
• Option Type: Provides Some and Null to handle optional values, similar to Option in Rust.
• Error Handling: Custom exceptions like UnwrapFailedError and TransposeError for robust error management.

Classes and Methods

Result

• and_then: Chains operations on Ok values.

  >>> assert Result.Ok(2).and_then(sq_then_to_string) == Ok("4")
  >>> assert Result.Err("Not a number").and_then(sq_then_to_string) == Err("Not a number")

• as_result: Decorator to convert function return values to Result.

  >>> @Result.as_result
  >>> def div(a: int, b: int) -> float:
  ...     return a / b
  >>> assert div(10, 2) == Result.Ok(5.0)
  >>> assert div(10, 0).map_err(str) == Result.Err("division by zero")

• from_fn: Executes a function and returns a Result.

• err, expect, expect_err: Methods to handle and retrieve error values.

• is_err, is_ok: Check the state of the result.

• map, map_err, map_or, map_or_else: Transform contained values.

• ok, or_else, unwrap, unwrap_err, unwrap_or, unwrap_or_else: Retrieve values with error handling.

Ok

• Represents a successful result.
• Methods to transform and retrieve the contained value.

Err

• Represents a failed result.
• Methods to handle and transform the error value.

Option

• Some: Represents an optional value.

  >>> assert Option.some(10) == Some(10)

• Null: Represents the absence of a value.

  >>> assert Option.null("Error") == Null("Error")

• from_fn, as_option: Methods to handle optional values.

Error Handling

• ResultError: Base class for result-related errors.
• UnwrapFailedError: Raised when an unwrap operation fails.
• OptionError: Base class for option-related errors.
• TransposeError: Raised when a transpose operation fails.

Project Structure

├── .python-version
├── pyproject.toml
├── README.md
├── uv.lock
├── src
│   └── results
│       ├── __init__.py
│       ├── py.typed
│       ├── results.py
│       └── results.pyi
└── tests
    ├── __init__.py
    └── results
        ├── __init__.py
        ├── test_factories.py
        ├── test_option.py
        ├── test_pattern_matching.py
        └── test_result.py