This is a regex implementation using Thompson's construction algorithm.
This was done just for educational purpose and I don`t think you should use this in production environments.
Supported meta characters:
| Meta character | Description |
|---|---|
| ? | zero or one |
| * | zero or more |
| | | alternate |
| + | one or more |
You can see more informations about how to create your own regex engine here (I used this article as a reference).