Table of Contents
About
def_result
is a library for python.
It is a library for functional error handling to improve managing errors.
It stores result of functions and provides a simple way to handle and manipulate the return values of functions, with
built-in support for error handling and more.
Purpose
In functional programming, it is not always appropriate to use traditional try-except
blocks because they can lead to
code that is difficult to read, understand, and maintain.
The purpose of Functional Error Handling Libraries is to provide developers with a set of abstractions and tools for
managing errors in a functional way.
def_result
is a functional error handling library. The goal of this library is to make error handling more explicit,
composable, and testable. By using this library, developers can write code that is more robust, maintainable, and
expressive.
Motivation
The motivation behind this library is the desire to write code that is more reliable, easier to understand, and less
prone to errors. In many cases, functional programming languages provide built-in abstractions for handling errors.
However, for languages that do not have built-in support for functional error handling, libraries like this can provide
a useful alternative.
What problems are solved?
This library can solve several problems, including:
- Ensuring that error handling is consistent across an application.
- Making it easier to test error handling code.
- Making error handling code more readable and maintainable.
- Encouraging developers to handle errors in a more functional way, which can lead to more reliable and robust code.
Developers can spend less time debugging and more time writing code that adds value to their organization. Additionally,
by using functional programming concepts, developers can write code that is easier to reason about and understand, which
can lead to faster development cycles and better quality code.
Getting Started
Use pip
to install package:
pip install def_result
Usage
Sample 1: use decorator for pure functions
In this example, def_result
is used as a decorator to wrap the divide_numbers
function.
from def_result import def_result
@def_result
def divide_numbers(a: int, b: int):
if b == 0:
raise ValueError("Cannot divide by zero")
return a / b
result = divide_numbers(10, 0)
if result.success:
print(f"Operation was successful: {result.value}")
else:
print(f"Operation failed: {str(result.detail)}")
Sample 2: use Result
in function
from def_result import Result
from def_result.ResultDetails.Errors import ValidationError
def divide_numbers(a: int, b: int):
if b == 0:
return Result.fail(ValidationError(message="Cannot divide by zero"))
return Result.ok(a / b)
result = divide_numbers(10, 0)
if result.success:
print(f"Operation was successful: {result.value}")
else:
print(f"Operation failed:")
print(str(result.detail))
CHANGELOG
Please see the CHANGELOG file.
Features
- Easy to use:
def_result
is designed to be simple and easy to use, with a minimal API and clear documentation. - Compatibility with existing code:
def_result
can be easily added to existing codes without the need for major
refactoring. You can use decorator for wrap old functions or write new functions without worrying about
incompatibilities. - Save any details you like: Thanks to
the ResultDetail class, you can store
various information about the output of the function. Also, by inheriting from this class, you can write new and
customized classes for your project.
- Special details for errors: With
the ErrorDetail class, you
can store specific details about errors. For example, this class supports stack trace in a built-in way.
- Support for common details by default:
In this link, you can see the different
types of details that are supported.
Roadmap
See the open issues for a list of proposed features (and known issues).
Support
Reach out to the maintainers at one of the following places:
FAQ
Do I need rewrite all the functions in a new way?
not necessarily. You can add this library and write new functions without changing the previous codes.
Also for old functions, you can use decorator. By using decorator, The output of the function is converted
to Result
format. This way, your code is wrap in a try-except
block to handle all exceptions.
How to manage all function exceptions?
By using decorator, your code is wrap in a try-except
block and the final output is converted to Result. In this way,
all exceptions are handled.
Project assistance
First of, thank you.
If you want to say thank you or/and support active development of def_result
:
- Add a GitHub Star to the project.
- Write interesting articles about the project on Dev.to, Medium or your
personal blog.
Together, we can make def_result
better!
Contributing
First off, thanks for taking the time to contribute! Contributions are what make the free/open-source community such an
amazing place to learn, inspire, and create. Any contributions you make will benefit everybody else and are greatly
appreciated.
Please read our contribution guidelines, and
thank you for being involved!
Please do not forget that this project uses conventional commits, so please
follow the specification in your commit messages. You can see valid types
from this file.
Authors & contributors
The original setup of this repository is by Payadel.
For a full list of all authors and contributors,
see the contributors page.
Security
def_result
follows good practices of security, but 100% security cannot be assured. def_result
is provided "as
is" without any warranty.
For more information and to report security issues, please refer to
our security documentation.
License
This project is licensed under the GPLv3.
See LICENSE for more information.