cdlre: JS-compatible regular expressions implemented in JS

This library is intended to help check the ECMAScript specification conformity of regular expression evaluations.

There are a bunch of potential applications:

• Regression testing the specification against host implementations.
• Use in understanding why regular expressions succeed/fail to match.
• Use in a metacircular interpreter.
• Use as a staging ground for regular expression optimizations and/or a regular expression compiler. (Such a compiler could target eval as a backend or a JIT code execution foreign function.)

Goals

• Be capable of visualizing (or at least dumping out) the ECMAScript standard steps taken in matching a regular expression.
• Be capable of enabling/disabling the de-facto quirks from various browsers which are not yet part of the standard.
• Be capable of running a thorough regression suite against the host regular expression engine (presumably with a set of permitted quirk options).
• Keep the JS code a direct translation from the spec where possible and practical.

Usage

Simple usage is as follows:

$ JS_SHELL=d8 make

Make targets

make test

Runs the entire test suite. Right now this is parser and evaluation (matcher) tests.

make hosted

Creates a directory structure that can be used for in-browser testing. If you subsequently run:

$ make hosted
...
$ cd hosted/
$ python -m SimpleHTTPServer
Serving HTTP on 0.0.0.0 port 8000 ...

You can navigate to the local testing site in your browser.

Directory structure

lib/

The regular expression library

test/

The regular expression library test suites

tools/

For automatically generating unicode bitmaps from the specification

generated/

Latest version of the generated unicode bitmaps

web/

The page that gets installed via the make hosted target