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//! Unicode identifiers.
use std::ops::Deref;
use unicode_xid::UnicodeXID;
/// An identifier as defined by unicode with a few extra permissible characters.
///
/// This is defined as in the [Unicode Standard], but allows additionally
/// `-` and `_` as starting and continuing characters.
///
/// [Unicode Standard]: http://www.unicode.org/reports/tr31/
#[derive(Debug, Clone, Eq, PartialEq, Ord, PartialOrd)]
pub struct Ident(pub String);
impl Ident {
/// Create a new identifier from a string checking that it is a valid.
pub fn new(ident: impl AsRef<str> + Into<String>) -> Option<Self> {
if is_ident(ident.as_ref()) {
Some(Self(ident.into()))
} else {
None
}
}
/// Return a reference to the underlying string.
pub fn as_str(&self) -> &str {
self
}
}
impl AsRef<str> for Ident {
fn as_ref(&self) -> &str {
self
}
}
impl Deref for Ident {
type Target = str;
fn deref(&self) -> &Self::Target {
self.0.as_str()
}
}
/// Whether the string is a valid identifier.
pub fn is_ident(string: &str) -> bool {
let mut chars = string.chars();
if matches!(chars.next(), Some(c) if c.is_xid_start() || is_also_ok(c)) {
chars.all(|c| c.is_xid_continue() || is_also_ok(c))
} else {
false
}
}
fn is_also_ok(c: char) -> bool {
c == '-' || c == '_'
}
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