Neat description of Reed-Solomon error codes and two simple error-correction algorithms, implemented in Python.
Found on https://planet.scheme.org/ via the article
https://jeremykun.com/2020/09/11/searching-for-rh-counterexamples-setting-up-pytest/

This page contains several computer programs, written in C/C++ language (and some Matlab scripts), that implement encoding and decoding routines of popular error correcting codes (ECC), such as Reed-Solomon codes, BCH codes, the binary Golay code, a binary Goppa code, a Viterbi decoder and more. Note that no effort has been made to `optimize' most of the algorithms used in the programs below. The algorithms work well, but by no means should be used as a basis for an implementation. All these programs are free to use for academic and personal purposes only. Use them at your own discretion.