pygoerrors

A Python library that brings Go-style error handling to Python, enabling error values, wrapping, and inspection without relying on exceptions.​

🚀 Features

• Error Values: Return errors as values instead of raising exceptions.
• Error Wrapping: Wrap errors with contextual messages, similar to Go's fmt.Errorf("...: %w", err).
• Error Inspection: Traverse error chains using unwrap(), is_(), and as_().
• Protocol-Based Design: Utilize Python's Protocol to define error interfaces.
• No Exceptions: Emphasize functional programming by avoiding exceptions entirely.​

📦 Installation

Install the package using pip:

pip install pygoerrors

🧑‍💻 Usage

Defining Custom Errors

import pygoerrors

MyOtherError = pygoerrors.new("some error")

class MyErrorClass(pygoerrors.Error):
    def error(self) -> str:
        return "some error"

Wrapping Errors

import pygoerrors

class MyErrorClass(pygoerrors.Error):
    def error(self) -> str:
        return "base error"

base_err = MyErrorClass()
assert base_err.error() == "base error"

wrapped_err = pygoerrors.errorf("wrapped: %w", base_err)
assert wrapped_err.error() == "wrapped: base error"

Inspecting Errors

import pygoerrors

class MyErrorClass(pygoerrors.Error):
    def error(self) -> str:
        return "base error"

base_err = MyErrorClass()
assert base_err.error() == "base error"

wrapped_err = pygoerrors.errorf("wrapped: %w", base_err)
assert wrapped_err.error() == "wrapped: base error"

assert pygoerrors.is_(wrapped_err, MyErrorClass())

instance = pygoerrors.as_(err, MyErrorClass)
assert instance.error() == "base error"