syn/
ident.rs

1#[cfg(feature = "parsing")]
2use crate::lookahead;
3
4pub use proc_macro2::Ident;
5
6#[cfg(feature = "parsing")]
7#[doc(hidden)]
#[allow(non_snake_case)]
pub(crate) fn Ident(marker: lookahead::TokenMarker) -> Ident {
    match marker {}
}pub_if_not_doc! {
8    #[doc(hidden)]
9    #[allow(non_snake_case)]
10    pub fn Ident(marker: lookahead::TokenMarker) -> Ident {
11        match marker {}
12    }
13}
14
15macro_rules! ident_from_token {
16    ($token:ident) => {
17        impl From<Token![$token]> for Ident {
18            fn from(token: Token![$token]) -> Ident {
19                Ident::new(stringify!($token), token.span)
20            }
21        }
22    };
23}
24
25impl From<crate::token::SelfValue> for Ident {
    fn from(token: crate::token::SelfValue) -> Ident {
        Ident::new("self", token.span)
    }
}ident_from_token!(self);
26impl From<crate::token::SelfType> for Ident {
    fn from(token: crate::token::SelfType) -> Ident {
        Ident::new("Self", token.span)
    }
}ident_from_token!(Self);
27impl From<crate::token::Super> for Ident {
    fn from(token: crate::token::Super) -> Ident {
        Ident::new("super", token.span)
    }
}ident_from_token!(super);
28impl From<crate::token::Crate> for Ident {
    fn from(token: crate::token::Crate) -> Ident {
        Ident::new("crate", token.span)
    }
}ident_from_token!(crate);
29impl From<crate::token::Extern> for Ident {
    fn from(token: crate::token::Extern) -> Ident {
        Ident::new("extern", token.span)
    }
}ident_from_token!(extern);
30
31impl From<crate::token::UnderscoreToken![_]> for Ident {
32    fn from(token: crate::token::UnderscoreToken![_]) -> Ident {
33        Ident::new("_", token.span)
34    }
35}
36
37pub(crate) fn xid_ok(symbol: &str) -> bool {
38    let mut chars = symbol.chars();
39    let first = chars.next().unwrap();
40    if !(first == '_' || unicode_ident::is_xid_start(first)) {
41        return false;
42    }
43    for ch in chars {
44        if !unicode_ident::is_xid_continue(ch) {
45            return false;
46        }
47    }
48    true
49}
50
51#[cfg(feature = "parsing")]
52mod parsing {
53    use crate::buffer::Cursor;
54    use crate::error::Result;
55    use crate::parse::{Parse, ParseStream};
56    use crate::token::Token;
57    use alloc::string::ToString;
58    use proc_macro2::Ident;
59
60    fn accept_as_ident(ident: &Ident) -> bool {
61        match ident.to_string().as_str() {
62            "_" |
63            // Based on https://doc.rust-lang.org/1.65.0/reference/keywords.html
64            "abstract" | "as" | "async" | "await" | "become" | "box" | "break" |
65            "const" | "continue" | "crate" | "do" | "dyn" | "else" | "enum" |
66            "extern" | "false" | "final" | "fn" | "for" | "if" | "impl" | "in" |
67            "let" | "loop" | "macro" | "match" | "mod" | "move" | "mut" |
68            "override" | "priv" | "pub" | "ref" | "return" | "Self" | "self" |
69            "static" | "struct" | "super" | "trait" | "true" | "try" | "type" |
70            "typeof" | "unsafe" | "unsized" | "use" | "virtual" | "where" |
71            "while" | "yield" => false,
72            _ => true,
73        }
74    }
75
76    #[cfg_attr(docsrs, doc(cfg(feature = "parsing")))]
77    impl Parse for Ident {
78        fn parse(input: ParseStream) -> Result<Self> {
79            input.step(|cursor| {
80                if let Some((ident, rest)) = cursor.ident() {
81                    if accept_as_ident(&ident) {
82                        Ok((ident, rest))
83                    } else {
84                        Err(cursor.error(format_args!("expected identifier, found keyword `{0}`", ident)format_args!(
85                            "expected identifier, found keyword `{}`",
86                            ident,
87                        )))
88                    }
89                } else {
90                    Err(cursor.error("expected identifier"))
91                }
92            })
93        }
94    }
95
96    impl Token for Ident {
97        fn peek(cursor: Cursor) -> bool {
98            if let Some((ident, _rest)) = cursor.ident() {
99                accept_as_ident(&ident)
100            } else {
101                false
102            }
103        }
104
105        fn display() -> &'static str {
106            "identifier"
107        }
108    }
109}
syn/ident.rs

syn/
ident.rs
