# PHPRegex

> Static analysis, linter & logic solver for PHP regular expressions. PHPRegex parses PCRE-style regexes into an immutable AST and answers questions about them: validity ruled as PHP's own engine would rule it, ReDoS safety with a proof or a witness, lint findings with fixes, provably equivalent rewrites, sample strings a pattern matches, and pattern-to-pattern logic (equivalence, intersection, subset) via automata.

Install: composer require --dev php-regex/php-regex:2.x-dev — the 2.x monorepo; the split packages (php-regex/regex-toolkit, regex-phpstan, ...) land on Packagist with 2.0.0
Docs: https://php-regex.com/docs/
Repository: https://github.com/php-regex/php-regex
License: MIT

## Learn

- [Documentation](https://php-regex.com/docs/): the documentation map, organized by task
- [Quick Start](https://php-regex.com/quick-start/): install and first analysis in a few runnable steps
- [Regex 101 tutorial](https://php-regex.com/tutorial/): regular expressions from basics to real-world PHP, ten chapters
- [Regex in PHP](https://php-regex.com/guides/regex-in-php/): how PCRE behaves inside preg_* — delimiters, flags, the functions and their return values

## Integrations

- [Guides index](https://php-regex.com/guides/): every integration on one page, with its install command
- [PHPStan](https://php-regex.com/guides/phpstan/): regex findings inside static analysis
- [Psalm](https://php-regex.com/guides/psalm/): $matches typed from the pattern
- [Rector](https://php-regex.com/guides/rector/): preg_* calls rewritten to the string functions they provably equal
- [Laravel](https://php-regex.com/guides/laravel/): Regex service, facade, artisan commands
- [Symfony](https://php-regex.com/guides/symfony/): bundle, service, console commands
- [LSP](https://php-regex.com/guides/lsp/): diagnostics, hovers and code actions in any editor
- [CLI](https://php-regex.com/guides/cli/): sixteen subcommands, config files, output formats, CI recipes
- [ReDoS guide](https://php-regex.com/guides/redos/): verdicts, guarantees, confirmed mode, fixes
- [Cookbook](https://php-regex.com/cookbook/): ready-made patterns with their safety verdicts
- [Troubleshooting](https://php-regex.com/troubleshooting/): common errors and their fixes

## Concepts

- [Key concepts](https://php-regex.com/concepts/): the fundamental ideas behind PHPRegex, explained for beginners
- [What is an AST?](https://php-regex.com/concepts/ast/): the structured representation of a pattern every analysis walks
- [Understanding Visitors](https://php-regex.com/concepts/visitors/): how operations run over the tree without changing it
- [ReDoS Deep Dive](https://php-regex.com/concepts/redos/): why patterns backtrack catastrophically and what is provable
- [PCRE vs Other Engines](https://php-regex.com/concepts/pcre/): where PHP's engine sits among the others

## Reference

- [Reference index](https://php-regex.com/reference/): the reference material on one page
- [Lint rules](https://php-regex.com/reference/rules/): every diagnostic, rule and optimization
- [API](https://php-regex.com/reference/api/): entry points, return objects, exceptions
- [Diagnostics](https://php-regex.com/reference/diagnostics/): error types, messages, and how to map them to fixes
- [Diagnostics cheat sheet](https://php-regex.com/reference/diagnostics-cheatsheet/): fast fixes for the most common diagnostics
- [JSON output](https://php-regex.com/reference/json-output/): every key the regex command prints
- [Feature support matrix](https://php-regex.com/reference/feature-support-matrix/): which PCRE construct each analysis layer supports
- [Correctness contracts](https://php-regex.com/reference/correctness-contracts/): what is sound, what is heuristic, per feature
- [Backward compatibility](https://php-regex.com/reference/backward-compatibility/): what each release may change
- [Capture shapes](https://php-regex.com/reference/capture-shapes/): what preg_match() writes into $matches
- [Pattern info](https://php-regex.com/reference/pattern-info/): the facts PCRE2 computes on every compiled pattern
- [Prefilters](https://php-regex.com/reference/prefilters/): when a string function can answer before preg_match()
- [PCRE2 conformance](https://php-regex.com/reference/pcre2-conformance/): measured against PHP's engine on the official test suite
- [Sonar](https://php-regex.com/reference/sonar/): where each SonarPHP regex rule maps to a PHPRegex identifier
- [Logic solver](https://php-regex.com/reference/logic-solver/): equivalence, intersection, subset, example strings
- [FAQ and Glossary](https://php-regex.com/reference/faq-glossary/): short answers and quick definitions
- [External References](https://php-regex.com/reference/resources/): the sources PHPRegex verifies diagnostics against

## Internals

- [Architecture](https://php-regex.com/architecture/): the lexer/parser/AST/visitor pipeline under the hood
- [AST traversal](https://php-regex.com/design/ast-traversal/): how the tree is walked, and in what order
- [Nodes](https://php-regex.com/nodes/): every AST node type, one per construct
- [Visitors](https://php-regex.com/visitors/): every built-in visitor, and how to build custom ones
- [Extending](https://php-regex.com/extending/): adding new PCRE features, visitors and integrations
- [Maintainers guide](https://php-regex.com/maintainers/): embedding PHPRegex in a tool as a first-class component

## Tutorial track

- [Introduction](https://php-regex.com/tutorial/): what the tutorial covers and the tools it uses
- [Chapter 1, Regex basics](https://php-regex.com/tutorial/01-basics/)
- [Chapter 2, Character classes & escapes](https://php-regex.com/tutorial/02-character-classes/)
- [Chapter 3, Anchors & boundaries](https://php-regex.com/tutorial/03-anchors-boundaries/)
- [Chapter 4, Quantifiers & greediness](https://php-regex.com/tutorial/04-quantifiers/)
- [Chapter 5, Groups & alternation](https://php-regex.com/tutorial/05-groups-alternation/)
- [Chapter 6, Lookarounds & assertions](https://php-regex.com/tutorial/06-lookarounds/)
- [Chapter 7, Backreferences & recursion](https://php-regex.com/tutorial/07-backreferences-recursion/)
- [Chapter 8, Performance & ReDoS](https://php-regex.com/tutorial/08-performance-redos/)
- [Chapter 9, Testing & debugging](https://php-regex.com/tutorial/09-testing-debugging/)
- [Chapter 10, Real-world PHP](https://php-regex.com/tutorial/10-real-world-php/)