regex

An interactive tool that visualizes regular expressions as a 3D marble run, making regex patterns easier to understand through playful, animated mechanics.

This article introduces a small JavaScript/TypeScript DSL inspired by Emacs' rx macro that lets developers write regular expressions as readable trees of named forms instead of opaque strings. It explains the internals (atoms, seqs, alts, quantifiers) and provides a cheat sheet, side-by-side examples, and a gist with the full source.

The blog post explores the effectiveness of generative testing versus unit tests in discovering bugs, using the Rust regex crate as a case study. It demonstrates how a custom fuzzer found multiple bugs and provides techniques for improving testing approaches.

The article explains the concept of labeled matches in regex for named entity recognition, compares its performance with spaCy's NER model, and showcases a tool called resharp that implements this feature efficiently.

The article investigates if regex can match valid credit card numbers by constructing a Deterministic Finite Automaton (DFA) based on the Luhn algorithm, resulting in a massive but executable regex pattern.

Python 3.15 soft deprecates the re.match() function, introducing re.prefixmatch() as a clearer alternative for pattern matching at the start of strings.

The blog post explains the soft deprecation of Python's re.match() function due to its surprising behavior and introduces a clearer alias, re.prefixmatch(), for Python 3.15.

The article explains how certgrep.sh, a free certificate transparency search engine with regex support, was built to address limitations in querying CT logs at scale for security applications, detailing its technical design and public release.

A developer recounts a three-week production bug where a regex with a literal backspace character silently disabled a language-detection guardrail, making the LLM appear flaky. The post highlights the need to instrument deterministic guardrails to distinguish them from model nondeterminism.

A tweet highlights Rob Pike's classic 30-line regular expression matcher in C, demonstrating recursion and pointer arithmetic as an introduction to regex engines.

A developer demonstrates running the game DOOM using a regex engine as a computational substrate, performing millions of substitutions per frame.

A new `regex!` macro has been released in the latest update of the Rust regex library, enabling compile-time regex compilation.

llama.cpp b9966 introduces a fix for the -sm tensor mode that caches regex patterns, eliminating 29 recompilations per tensor per token on the decode thread, resulting in significantly reduced CPU overhead.

An article investigating platform support for GNU extensions to Basic Regular Expressions (BRE), specifically the `\+` operator, and finding it works on FreeBSD, macOS, and musl-based distributions like Chimera Linux.

The article discusses the challenges of regex portability across tools like sed, awk, grep, and Emacs, and provides a subset of regex features that work reliably across these environments.

A deep dive into the limitations of regex for parsing HTML, inspired by the famous Stack Overflow answer, discussing formal language theory and the power of industrial regex engines.

A blog post debunking common misconceptions about validating email addresses, arguing against regex-based validation and advocating for simpler verification methods like sending a confirmation email.

Nicholas Carlini's project implements a 2-ply minimax chess engine using 84,688 regular expressions, executed sequentially to play valid chess moves. The post explains the design of a regular expression computer that interprets instructions.

The author analyzes 262,715 Stack Overflow questions to identify common regex pain points and demonstrates how their new regex engine, RE#, solves these issues using complement and intersection operations.

A minimal Python ctypes binding to the TRE regex library demonstrates robust performance against ReDoS attacks, processing evil patterns on 10M-character inputs much faster than Python's re module.