Regrets

Use Z3 to generate strings that match multiple regex!

The plural of regex is regrets

WARNING: regrets is still in development! If you have any feedback or suggestions to improve it, let me know!

Setup

To use regrets, you need to

• Clone this repository
• Install all requirements (Z3 and Typer, via pip install -r requirements.txt)
• Run regrets!

How to use

You can use regrets to generate strings that would be matched by a given regex

$ python main.py --matching "[A-Za-z0-9]{3,10}"

AnP

You can also have multiple --matching options! This will generate strings that match all provided regex.

$ python main.py --matching "[A-Za-z0-9]{3,10}" --matching "abcd[0-9]+"

abcd4

If you want, you can also add a list of regex that the string should NOT match:

$ python main.py --matching "[A-Za-z0-9]{3,10}" --matching "abcd[0-9]+" --not-matching "[a-z]{4}[1-4]"

abcd6

You can also exclude patterns entirely. For example, do you want to exclude all lowercase chars ([a-z])?

$ python main.py --matching "[A-Za-z0-9]{3,10}" --not-partial-matching "[a-z]"           

0KX

You can find all available options from --help

Current Limitations

• regrets does NOT support PCRE at the moment (yeah I know, that kinda sucks... but many regex can still be converted or adapted to the non-PCRE counterpart, e.g., Negative Lookaheads)
• The current regex-to-Z3 converter (credits to Andrew Helwer for the original code) does not support all regex constructs at the moment (e.g., lazy quantifiers such as *?, +?, and ??). PRs are welcome!
• Z3 is very powerful, but it can sometimes be VERY (and I mean VERY) slow if the regex is very complex. Be patient :D
• Multiple runs of regrets with the same parameters will yield the same results. This is due to the deterministic nature of Z3. If you want different results, simply run regrets with a high -N parameter (an update that excludes previously seen strings is coming soon)

How to Contribute

PRs for missing features and overcoming limitations are always welcome!

But also, any feedback regarding usability or performance of regrets would be great!

Also, if you're using (and possibly enjoying) regrets in your projects, let me know your use case!