An error when parsing regex.

[zigazajc007]

What version of regex are you using?

1.5.5

Describe the bug at a high level.

An error when parsing regex.

What are the steps to reproduce the behavior?

use regex::Regex;

struct Validate{}

impl Validate{
  fn password(password:&str)->bool{
    return Regex::new(r"^(?=.*[A-Za-z])(?=.*\d)(?=.*[@$!%*#?&,_\(\)\=\-\.])[A-Za-z\d@$!%*#?&,_\(\)\=\-\.]{8,255}$").unwrap().is_match(password);
  }
}

fn main() {
  println!("Is password valid? {}", Validate::password("RandomGeneratedPassword123!"));
}

What is the actual behavior?

thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Syntax(
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
regex parse error:
    ^(?=.*[A-Za-z])(?=.*\d)(?=.*[@$!%*#?&,_\(\)\=\-\.])[A-Za-z\d@$!%*#?&,_\(\)\=\-\.]{8,255}$
     ^^^
error: look-around, including look-ahead and look-behind, is not supported
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
)', src/main.rs:11:121
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

What is the expected behavior?

To be able to parse this regex. The same regex also works in PHP and JavaScript.

[BurntSushi]

This isn't a bug, as the error incidates. The very first sentences of the docs for this crate state:

This crate provides a library for parsing, compiling, and executing regular expressions. Its syntax is similar to Perl-style regular expressions, but lacks a few features like look around and backreferences. In exchange, all searches execute in linear time with respect to the size of the regular expression and search text.