| name | regex | op |
| - | - | - |
| concat | ab | a & b |
| alternation | a\|b | a \| b |
| kleen star | a* | [a] |
| optional | a? | a? |
| repetition | a{n,m} | a * (n..m) |
| class | [a-z] | 'a'..'z' |
| negation | [^a-z] | !('a'..'z') |
TODO