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// Copyright 2012-2024 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! Determine if a `char` is a valid identifier for a parser and/or lexer according to
//!
//! ```rust
//! use unicode_xid::UnicodeXID;
//!
//! fn main() {
//! assert_eq!(UnicodeXID::is_xid_start('a'), true); // 'a' is a valid start of an identifier
//! assert_eq!(UnicodeXID::is_xid_start('△'), false); // '△' is a NOT valid start of an identifier
//! }
//! ```
//!
//! # features
//!
//! unicode-xid supports a `no_std` feature. This eliminates dependence
//! on std, and instead uses equivalent functions from core.
//!
#![forbid(unsafe_code)]
#![deny(missing_docs)]
#
)]
#![no_std]
#![cfg_attr(feature = "bench", feature(test, unicode_internals))]
#[cfg(test)]
#[macro_use]
extern crate std;
#[cfg(feature = "bench")]
extern crate test;
use tables::derived_property;
pub use tables::UNICODE_VERSION;
mod tables;
#[cfg(test)]
mod tests;
/// Methods for determining if a character is a valid identifier character.
pub trait UnicodeXID {
/// Returns whether the specified character satisfies the 'XID_Start'
/// Unicode property.
///
/// 'XID_Start' is a Unicode Derived Property specified in
/// mostly similar to ID_Start but modified for closure under NFKx.
fn is_xid_start(self) -> bool;
/// Returns whether the specified `char` satisfies the 'XID_Continue'
/// Unicode property.
///
/// 'XID_Continue' is a Unicode Derived Property specified in
/// mostly similar to 'ID_Continue' but modified for closure under NFKx.
fn is_xid_continue(self) -> bool;
}
impl UnicodeXID for char {
#[inline]
fn is_xid_start(self) -> bool {
// Fast-path for ascii idents
('a' <= self && self <= 'z')
|| ('A' <= self && self <= 'Z')
|| (self > '\x7f' && derived_property::XID_Start(self))
}
#[inline]
fn is_xid_continue(self) -> bool {
// Fast-path for ascii idents
('a' <= self && self <= 'z')
|| ('A' <= self && self <= 'Z')
|| ('0' <= self && self <= '9')
|| self == '_'
|| (self > '\x7f' && derived_property::XID_Continue(self))
}
}