1 #[cfg(feature = "parsing")] 2 use crate::buffer::Cursor; 3 #[cfg(feature = "parsing")] 4 use crate::lookahead; 5 #[cfg(feature = "parsing")] 6 use crate::parse::{Parse, ParseStream, Result}; 7 #[cfg(feature = "parsing")] 8 use crate::token::Token; 9 use unicode_xid::UnicodeXID; 10 11 pub use proc_macro2::Ident; 12 13 #[cfg(feature = "parsing")] 14 #[doc(hidden)] 15 #[allow(non_snake_case)] Ident(marker: lookahead::TokenMarker) -> Ident16pub fn Ident(marker: lookahead::TokenMarker) -> Ident { 17 match marker {} 18 } 19 20 #[cfg(feature = "parsing")] accept_as_ident(ident: &Ident) -> bool21fn accept_as_ident(ident: &Ident) -> bool { 22 match ident.to_string().as_str() { 23 "_" | 24 // Based on https://doc.rust-lang.org/grammar.html#keywords 25 // and https://github.com/rust-lang/rfcs/blob/master/text/2421-unreservations-2018.md 26 // and https://github.com/rust-lang/rfcs/blob/master/text/2420-unreserve-proc.md 27 "abstract" | "as" | "become" | "box" | "break" | "const" | "continue" | 28 "crate" | "do" | "else" | "enum" | "extern" | "false" | "final" | "fn" | 29 "for" | "if" | "impl" | "in" | "let" | "loop" | "macro" | "match" | 30 "mod" | "move" | "mut" | "override" | "priv" | "pub" | "ref" | 31 "return" | "Self" | "self" | "static" | "struct" | "super" | "trait" | 32 "true" | "type" | "typeof" | "unsafe" | "unsized" | "use" | "virtual" | 33 "where" | "while" | "yield" => false, 34 _ => true, 35 } 36 } 37 38 #[cfg(feature = "parsing")] 39 impl Parse for Ident { parse(input: ParseStream) -> Result<Self>40 fn parse(input: ParseStream) -> Result<Self> { 41 input.step(|cursor| { 42 if let Some((ident, rest)) = cursor.ident() { 43 if accept_as_ident(&ident) { 44 return Ok((ident, rest)); 45 } 46 } 47 Err(cursor.error("expected identifier")) 48 }) 49 } 50 } 51 52 #[cfg(feature = "parsing")] 53 impl Token for Ident { peek(cursor: Cursor) -> bool54 fn peek(cursor: Cursor) -> bool { 55 if let Some((ident, _rest)) = cursor.ident() { 56 accept_as_ident(&ident) 57 } else { 58 false 59 } 60 } 61 display() -> &'static str62 fn display() -> &'static str { 63 "identifier" 64 } 65 } 66 67 macro_rules! ident_from_token { 68 ($token:ident) => { 69 impl From<Token![$token]> for Ident { 70 fn from(token: Token![$token]) -> Ident { 71 Ident::new(stringify!($token), token.span) 72 } 73 } 74 }; 75 } 76 77 ident_from_token!(self); 78 ident_from_token!(Self); 79 ident_from_token!(super); 80 ident_from_token!(crate); 81 ident_from_token!(extern); 82 83 impl From<Token![_]> for Ident { from(token: Token![_]) -> Ident84 fn from(token: Token![_]) -> Ident { 85 Ident::new("_", token.span) 86 } 87 } 88 xid_ok(symbol: &str) -> bool89pub fn xid_ok(symbol: &str) -> bool { 90 let mut chars = symbol.chars(); 91 let first = chars.next().unwrap(); 92 if !(UnicodeXID::is_xid_start(first) || first == '_') { 93 return false; 94 } 95 for ch in chars { 96 if !UnicodeXID::is_xid_continue(ch) { 97 return false; 98 } 99 } 100 true 101 } 102