This repository contains a single Python script with one sordid purpose: to create regular expressions that test a number n in base b for divisibility by a divisor d. Horrifying, right?
The basis for these regexes abominations are Deterministic Finite Automata, a type of state machine that accepts symbols that transition it from state to state. A DFA that accepts only divisible numbers is simple to construct, and a description of this process can be found here.
The Python script within this repository can do one of two things:
- It can generate a
.jfffile containing a DFA for divisibility, which should then be imported into JFLAP for conversion to a plain regex. However, formal languageregexesabominations use a different syntax than programmer regexes., which means you will have to find & replace all+characters with|characters to get a usable regex. - It can, directly from the command line, generate a regex using recursion that is much smaller and faster than the JFLAP version. However, this regex will (obviously) only work in a regex engine that supports recursion.
Godspeed and have fun
As with many projects, the original inspiration for project was a simple thought: why am I not dead yet. However, unwilling and unable to take matters into my own hands*, I decided that generating regexes abominations of obscene size and complexity with no usefulness whatsoever was the next best thing.
* This is a joke.
The inspiration for this project came from the stack overflow post linked above. I noticed numerous people presenting their already constructed regexes abominations, but no simple and thorough process that allows someone with little knowledge about formal languages to construct their own regexes abominations.
If you post any of these regexes to a forum or stack exchange, please link people here. I worked reasonably hard on this and even downloaded an ebook on formal languages just to complete this project.
This project is entirely a joke. It is a ridiculous project leveraging some math and formal languages to do something that regexes weren't designed for. Any ridiculous statements inside this project are purely satire.