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use regex::Regex;
use std::fmt::{self, Display, Formatter};
use std::ops::{Add, BitOr};
pub trait Element: Add<Rec> + BitOr<Rec> {
fn into_rec(self) -> Rec;
fn group(self) -> Rec
where
Self: Sized,
{
self.into_rec().group()
}
fn unionable_value(&self) -> Option<String> {
None
}
}
impl Element for &str {
#[inline]
fn into_rec(self) -> Rec {
Rec(self
.replace(".", r"\.")
.replace("+", r"\+")
.replace("*", r"\*")
.replace("?", r"\?")
.replace("|", r"\|")
.replace("[", r"\[")
.replace("]", r"\]"))
}
fn unionable_value(&self) -> Option<String> {
if self.len() == 1 {
Some(String::from(*self))
} else {
None
}
}
}
impl Add<Rec> for &'_ str {
type Output = Rec;
#[inline]
fn add(self, rhs: Rec) -> Self::Output {
Rec(format!("{}{}", self.into_rec(), rhs))
}
}
impl BitOr<Rec> for &'_ str {
type Output = Rec;
fn bitor(self, rhs: Rec) -> Self::Output {
Rec(format!("{}|{}", self.into_rec(), rhs))
}
}
impl Element for String {
#[inline]
fn into_rec(self) -> Rec {
Rec(self)
}
}
impl Add<Rec> for String {
type Output = Rec;
fn add(self, rhs: Rec) -> Self::Output {
Rec(format!("{}{}", self.into_rec(), rhs))
}
}
impl BitOr<Rec> for String {
type Output = Rec;
fn bitor(self, rhs: Rec) -> Self::Output {
Rec(format!("{}|{}", self.into_rec(), rhs))
}
}
#[derive(Clone, Eq, PartialEq, Hash, Debug, Default)]
pub struct Rec(String);
impl Rec {
#[allow(clippy::result_unwrap_used)]
#[inline]
pub fn build(self) -> Regex {
self.try_build().unwrap()
}
fn group(self) -> Self {
let length = self.0.chars().count();
if length > 2 || (length == 2 && self.0.chars().nth(0) != Some('\\')) {
return Self(format!("(?:{})", self));
}
self
}
pub(crate) fn try_build(&self) -> Result<Regex, regex::Error> {
Regex::new(&self.0)
}
}
impl<Rhs: Element> Add<Rhs> for Rec {
type Output = Self;
#[inline]
fn add(self, rhs: Rhs) -> Self {
Self(format!("{}{}", self, rhs.into_rec()))
}
}
impl<T: Element> BitOr<T> for Rec {
type Output = Self;
#[inline]
fn bitor(self, rhs: T) -> Self {
let new = Self(format!("{}|{}", self.0, rhs.into_rec()));
new.group()
}
}
impl Display for Rec {
#[inline]
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
write!(f, "{}", self.0)
}
}
impl Element for Rec {
#[inline]
fn into_rec(self) -> Self {
self
}
}