Do you support Wildcard?

[odats]

The wildcard . matches any character. For example, a.b matches any string that contains an "a", then any other character and then "b", a.*b matches any string that contains an "a", and then the character "b" at some later point.
https://en.wikipedia.org/wiki/Regular_expression

I have tried a.*b and system generate strange DFA and NFA. None of them work correctly.

[izuzak]

👋 Hey, @odats! No, there's no such wildcard support in the tools. The supported features are documented on the page:

http://ivanzuzak.info/noam/webapps/regex_simplifier/

A valid regex consists of alphanumeric characters representing the set of input symbols (e.g. a, B, 9), the $ character representing the empty string, the choice operator +, the Kleene operator *, and parentheses ( and ).

It'd be neat to have support for a wildcard character, but that's not the primary focus of these tools. These tools have an educational focus -- they're here to help folks who are learning about theoretical computer science (languages, grammars, and automatons). The tools are not focused on supporting all the features that are present in most regex libraries found in popular programming language frameworks.

I'll keep this open as a feature request, since I'm definitely not 👎 on adding such a feature. I probably won't have time to work on such a feature anytime soon, so if someone else wants to give it a try and open a pull request -- I'd be happy to review it.