// include the latest version of the regex crate in your Cargo.toml
extern crate regex;
use regex::Regex;
fn main() {
let regex = Regex::new(r"(?mx)(?<!\\) # negative look-behind to make sure start is not escaped
(?: # start non-capture group for all possible match starts
# group 1, match dollar signs only
# single or double dollar sign enforced by look-arounds
((?<!\$)\${1,2}(?!\$))|
# group 2, match escaped parenthesis
(\\\()|
# group 3, match escaped bracket
(\\\[)|
# group 4, match begin equation
(\\begin\{equation\})
)
# if group 1 was start
(?(1)
# non greedy match everything in between
# group 1 matches do not support recursion
(.*?)(?<!\\)
# match ending double or single dollar signs
(?<!\$)\1(?!\$)|
# else
(?:
# greedily and recursively match everything in between
# groups 2, 3 and 4 support recursion
(.*(?R)?.*)(?<!\\)
(?:
# if group 2 was start, escaped parenthesis is end
(?(2)\\\)|
# if group 3 was start, escaped bracket is end
(?(3)\\\]|
# else group 4 was start, match end equation
\\end\{equation\}
)
))))").unwrap();
let string = "NOTE: For test purposes each test has been contained to one line, please enable the s flag for multi-line matches.
$ match $ don't match nested $ match $
$$ no match$
$no match$$
\\\\$no match\\\\$
$no match\\\\$
\\\\$no match\\\\$
$$ match $$ don't match nested $$ match $$
$$$ no match $$
$$ no match $$$
\\\\$$ no match$$
$$ no match\\\\$$
\\\\$$ no match\\\\$$
\\( match \\)
\\( 1 \\( nested match \\) 3 \\)
\\\\( no match \\\\)
\\( no match \\\\\\\\)
\\\\\\\\( no match \\\\\\\\)
\\[ match \\]
\\[ 1 \\[ nested match \\] 3 \\]
\\\\\\\\[ no match \\\\]
\\\\[ no match \\\\\\\\]
\\\\\\\\[ no match \\\\\\\\]
\\begin{equation} match \\end{equation}
\\begin{equation} 1 \\begin{equation} nested match \\end{equation} \\end{equation}
\\\\\\\\begin{equation} no match \\\\end{equation}
\\\\begin{equation} no match \\\\\\\\end{equation}
\\\\\\\\begin{equation} no match \\\\end{equation}";
// result will be an iterator over tuples containing the start and end indices for each match in the string
let result = regex.captures_iter(string);
for mat in result {
println!("{:?}", mat);
}
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Rust, please visit: https://docs.rs/regex/latest/regex/