The characters or syntax used in the game
| Characters | Description |
|---|---|
| | | Alternation |
| \d | Digit |
| \D | Not a digit |
| \w | Word character |
| \W | Not a word character |
| \s | Whitespace character |
| \S | Not a whitespace character |
| [a-z] | Character class |
| [^a-z] | Negated character class |
| * | Quantifier 0 or more occurrences |
| + | Quantifier 1 or more occurrences |
| ? | Quantifier 0 or 1 occurrence |
| {2,} | Quantifier 2 or more occurrences |
| {1,4} | Quantifier 1 to 4 occurrences |
| \b | Word boundary |
| \B | Not a word boundary |
| ^ | Start of the string |
| $ | End of string |
| \G | Position at the end of the previous match or start of the string |
| \K | All that is matched so far is not part of the returned match |
| \1 | Backreference to capture group 1 |
| (?= | Positive lookahead |
| (?! | Negative lookahead |
| (?<= | Positive lookbehind |
| (?<! | Negative lookbehind |
| (...) | Capture group |
| (?:...) | Non capture group |