Regex Grammar


- infinite repetition (`+`, `*`)
- finite repetition (`{n}`)
- any single character (`.`)
- range of characters (`-`) (e.g. `[abc]` or `[acb]` or `[0-9]`
> - `[^` means excep
- not (`~`)
- optional (`?`)
### Regex Grammars
|Title|
|:-:|
|[Regex Nested Expression](https://texonom.com/regex-nested-expression-f21810b7d79941269b300d893c0ac3d7)|


- letter - `[a-zA-Z]`
- digit - `[0-9]`









