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extern crate regex;
pub trait RegexStruct {
fn find(&self, text: &str) -> Self;
}
pub struct Restruct;
impl Restruct {
pub fn fill<T: RegexStruct>(regex_struct: &T, text: &str) -> T {
regex_struct.find(text)
}
}
#[macro_export]
macro_rules! regexify {
($name : ident {
$($field : ident, $field_type : ty, $pattern : expr)*
}) => {
struct $name {
$(
$field: $field_type,
)*
_regex : Regex
}
impl Default for $name {
fn default() -> $name {
let mut regex = String::new();
$(
match stringify!($field) {
x if x.starts_with("_") => {
regex.push_str($pattern);
},
y => {
let named_capture = format!("(?P<{}>{})", y, $pattern);
regex.push_str(&named_capture);
}
}
)*
$name {
$($field : Default::default(),)*
_regex : Regex::new(regex.as_str()).unwrap()
}
}
}
impl RegexStruct for $name {
fn find(&self, text: &str) -> $name {
let captures = self._regex.captures(text).unwrap();
let mut filled : $name = Default::default();
$(
if let Some(value) = captures.name(stringify!($field)) {
filled.$field = value.as_str().parse::<$field_type>().unwrap();
}
)*
filled
}
}
}
}
#[cfg(test)]
mod test {
use regex::Regex;
use super::{Restruct, RegexStruct};
#[test]
fn single_struct_regex() {
regexify!(SemVer {
major, i32, r"\d+"
__1, String, r"\."
minor, i32, r"\d+"
__2, String, r"\."
patch, i32, r"\d+"
});
let version: SemVer = Default::default();
assert_eq!(r"(?P<major>\d+)\.(?P<minor>\d+)\.(?P<patch>\d+)",
version._regex.as_str());
}
#[test]
fn single_struct_with_same_types() {
regexify!(HostName {
domain, String, r"\w+"
_dot, String, r"\."
tld, String, r"\w+"
});
let host: HostName = Default::default();
let filled_host = Restruct::fill(&host, "example.com");
assert_eq!("example", filled_host.domain);
assert_eq!("com", filled_host.tld);
}
#[test]
fn single_struct_with_diff_types() {
regexify!(Movies {
title, String, r"'[^']+'"
_1, String, r"\s+\("
year, i32, r"\d+"
_2, String, r"\)"
});
let movie: Movies = Default::default();
let filled_movie = Restruct::fill(&movie, "Not my favorite movie: 'Citizen Kane' (1941).");
assert_eq!(r"'Citizen Kane'", filled_movie.title);
assert_eq!(1941, filled_movie.year);
}
}