# Engine assets

Regex Tools executes ECMAScript through the browser's native `RegExp` engine.
It also ships ten declared, self-hosted runtime packs:

- `pcre2/`: official standalone PCRE2 10.47, 8-bit WebAssembly;
- `php/`: PHP 8.5.8 `preg_*` through `@php-wasm/web-8-5` 3.1.46; this runtime
  reports PCRE2 10.44;
- `perl/`: Perl 5.28.1 through the legacy WebPerl 0.09-beta prebuilt runtime;
- `python/`: Pyodide 314.0.3 with CPython 3.14.2 `re`, a complete linked
  base-runtime inventory (including vendored loader ports),
  preferred-form/patch manifest and independently pinned legal closure;
- `ruby/`: minimal ruby.wasm 2.9.3-2.9.4 with CRuby 4.0.0 `Regexp`;
- `java/`: TeaVM 0.15.0's `java.util.regex` class library compiled to an
  ES2015 module; this module is not OpenJDK;
- `cpp/`: Emscripten 6.0.4 libc++ `std::wregex`, with an exact traced native
  component/source/legal manifest;
- `go/`: Go 1.26.5 standard-library `regexp` for `js/wasm`;
- `rust/`: Rust `regex` crate 1.13.1 for `wasm32-unknown-unknown`; and
- `dotnet/`: .NET 10.0.10 `System.Text.RegularExpressions` for browser
  WebAssembly.

The selectable Scala/JVM compatibility profile intentionally shares
`java/`. It does not contain or claim a Scala runtime.

The packs come from pinned, documented open-source inputs. Runtime files travel
with deterministic metadata, closed-set checksums and the applicable upstream
licence/notice material, all of which are verified by the release gate.
The Python pack's `SOURCE-MANIFEST.json` records exact source archives or Git
trees, both vendored stack-parser source ports, all Pyodide
CPython/Emscripten patches and the evidence for every component already linked
into its loader or base WebAssembly module. The C++ source manifest similarly
binds its exact module to the traced Emscripten runtime, musl, emmalloc,
compiler-rt, libc++ and libc++abi inputs and the explicit non-selection of
libunwind. The
hundreds of optional entries in `pyodide-lock.json` are a package catalogue;
their wheels are not part of this pack.

The Perl pack remains an explicit exception in age, not in identity: its
upstream beta assets are retained byte-for-byte and labelled legacy everywhere.
Its loader contains a dormant optional JavaScript-interoperability `eval` site;
the fixed bridge does not import or call it.