fastdiff

0.3.0 · active · verified Sat Apr 11

fastdiff is a Python library (current version 0.3.0) that offers a fast, native implementation of a diff algorithm, including a pure Python fallback. It re-implements the core functionality of Python's built-in `difflib` by leveraging Rust compiled to WebAssembly, which can lead to significant performance improvements for string comparisons. The project has an infrequent release cadence, with its last update in May 2021.

Warnings

gotcha Despite reaching version 0.3.0, the library is officially classified as '2 - Pre-Alpha' on PyPI. This indicates it might not be production-ready, could have unstable APIs, or be subject to significant changes without a major version bump.
Fix: Review the project's GitHub for recent activity or explicit stability guarantees if using in a production environment.
gotcha The advertised performance benefits of fastdiff are contingent on the successful loading and execution of its native WebAssembly component. If the underlying `wasmer` runtime or the WASM binary encounters issues, the library will silently fall back to a pure Python implementation, effectively losing its speed advantage without explicit warnings to the user.
Fix: Consider benchmarking your specific use case to confirm native performance is active. Ensure your environment is compatible with `wasmer` and WebAssembly execution.
gotcha The project exhibits a slow maintenance pace, with the last release (0.3.0) in May 2021. Users should be aware that new features, bug fixes, or compatibility updates for newer Python versions or underlying technologies might not be frequent.
Fix: Evaluate if the current feature set and stability meet your needs, as future development may be limited.

Install

pip install fastdiff Install stable release

Imports

compare
```
from fastdiff import compare
```
The primary function for comparing two strings.

Quickstart

This example demonstrates how to import the `compare` function and use it to find the differences between two multi-line strings. The `compare` function returns an iterator of diff operations similar to `difflib`.

from fastdiff import compare

str1 = 'hello\nworld\npython\n'
str2 = 'hello\nwasm\npython\n'

diff_result = compare(str1, str2)
print(list(diff_result))

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