Regex Syntax
Supported Features
| Feature |
Syntax |
Example |
| Literals |
abc |
abc |
| Dot (any character) |
. |
.{5} |
| Character classes |
[abc], [a-z], [^0-9] |
[A-Za-z_] |
| Shorthand classes |
\d, \D, \w, \W, \s, \S |
\d{4} |
| Negated literal |
[^x] |
[^a] |
| Quantifiers |
{n}, {n,m}, *, +, ? |
\w{3,8} |
| Lazy quantifiers |
{n,m}?, *?, +?, ?? |
\d{1,5}? |
| Groups |
(...) |
(abc) |
| Alternation |
a\|b |
(yes\|no) |
| Backreferences |
\1, \2 |
(a)\1 |
| Anchors |
^, $ |
^\d+$ |
| Lookahead |
(?=...) |
(?=prefix) |
| Negative lookahead |
(?!...) |
(?!skip) |
Limitations
- Unbounded quantifiers capped —
*, +, and {n,} default to 100 repetitions (configurable via max_repeat or configure())
- No conditional backreferences —
(?(id)yes|no) syntax is not supported
- Anchors are ignored —
^ and $ do not constrain output; they are treated as empty strings
- Negative lookahead is ignored —
(?!...) always produces an empty string
- Not a regex validator — the library generates strings matching the parsed AST, but does not guarantee coverage of all possible matches