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#[cfg(feature = "parsing")]
use crate::buffer::Cursor;
#[cfg(feature = "parsing")]
use crate::lookahead;
#[cfg(feature = "parsing")]
use crate::parse::{Parse, ParseStream, Result};
#[cfg(feature = "parsing")]
use crate::token::Token;
use unicode_xid::UnicodeXID;
pub use proc_macro2::Ident;
#[cfg(feature = "parsing")]
#[doc(hidden)]
#[allow(non_snake_case)]
pub fn Ident(marker: lookahead::TokenMarker) -> Ident {
match marker {}
}
#[cfg(feature = "parsing")]
fn accept_as_ident(ident: &Ident) -> bool {
match ident.to_string().as_str() {
"_" |
// Based on https://doc.rust-lang.org/grammar.html#keywords
// and https://github.com/rust-lang/rfcs/blob/master/text/2421-unreservations-2018.md
// and https://github.com/rust-lang/rfcs/blob/master/text/2420-unreserve-proc.md
"abstract" | "as" | "become" | "box" | "break" | "const" | "continue" |
"crate" | "do" | "else" | "enum" | "extern" | "false" | "final" | "fn" |
"for" | "if" | "impl" | "in" | "let" | "loop" | "macro" | "match" |
"mod" | "move" | "mut" | "override" | "priv" | "pub" | "ref" |
"return" | "Self" | "self" | "static" | "struct" | "super" | "trait" |
"true" | "type" | "typeof" | "unsafe" | "unsized" | "use" | "virtual" |
"where" | "while" | "yield" => false,
_ => true,
}
}
#[cfg(feature = "parsing")]
impl Parse for Ident {
fn parse(input: ParseStream) -> Result<Self> {
input.step(|cursor| {
if let Some((ident, rest)) = cursor.ident() {
if accept_as_ident(&ident) {
return Ok((ident, rest));
}
}
Err(cursor.error("expected identifier"))
})
}
}
#[cfg(feature = "parsing")]
impl Token for Ident {
fn peek(cursor: Cursor) -> bool {
if let Some((ident, _rest)) = cursor.ident() {
accept_as_ident(&ident)
} else {
false
}
}
fn display() -> &'static str {
"identifier"
}
}
macro_rules! ident_from_token {
($token:ident) => {
impl From<Token![$token]> for Ident {
fn from(token: Token![$token]) -> Ident {
Ident::new(stringify!($token), token.span)
}
}
};
}
ident_from_token!(self);
ident_from_token!(Self);
ident_from_token!(super);
ident_from_token!(crate);
ident_from_token!(extern);
impl From<Token![_]> for Ident {
fn from(token: Token![_]) -> Ident {
Ident::new("_", token.span)
}
}
pub fn xid_ok(symbol: &str) -> bool {
let mut chars = symbol.chars();
let first = chars.next().unwrap();
if !(UnicodeXID::is_xid_start(first) || first == '_') {
return false;
}
for ch in chars {
if !UnicodeXID::is_xid_continue(ch) {
return false;
}
}
true
}
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