1 #[cfg(feature = "parsing")]
2 use crate::lookahead;
3
4 pub use proc_macro2::Ident;
5
6 #[cfg(feature = "parsing")]
7 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
15 macro_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
25 ident_from_token!(self);
26 ident_from_token!(Self);
27 ident_from_token!(super);
28 ident_from_token!(crate);
29 ident_from_token!(extern);
30
31 impl From<Token![_]> for Ident {
from(token: Token![_]) -> Ident32 fn from(token: Token![_]) -> Ident {
33 Ident::new("_", token.span)
34 }
35 }
36
xid_ok(symbol: &str) -> bool37 pub(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")]
52 mod parsing {
53 use crate::buffer::Cursor;
54 use crate::error::Result;
55 use crate::parse::{Parse, ParseStream};
56 use crate::token::Token;
57 use proc_macro2::Ident;
58
accept_as_ident(ident: &Ident) -> bool59 fn accept_as_ident(ident: &Ident) -> bool {
60 match ident.to_string().as_str() {
61 "_" |
62 // Based on https://doc.rust-lang.org/1.65.0/reference/keywords.html
63 "abstract" | "as" | "async" | "await" | "become" | "box" | "break" |
64 "const" | "continue" | "crate" | "do" | "dyn" | "else" | "enum" |
65 "extern" | "false" | "final" | "fn" | "for" | "if" | "impl" | "in" |
66 "let" | "loop" | "macro" | "match" | "mod" | "move" | "mut" |
67 "override" | "priv" | "pub" | "ref" | "return" | "Self" | "self" |
68 "static" | "struct" | "super" | "trait" | "true" | "try" | "type" |
69 "typeof" | "unsafe" | "unsized" | "use" | "virtual" | "where" |
70 "while" | "yield" => false,
71 _ => true,
72 }
73 }
74
75 #[cfg_attr(doc_cfg, doc(cfg(feature = "parsing")))]
76 impl Parse for Ident {
parse(input: ParseStream) -> Result<Self>77 fn parse(input: ParseStream) -> Result<Self> {
78 input.step(|cursor| {
79 if let Some((ident, rest)) = cursor.ident() {
80 if accept_as_ident(&ident) {
81 Ok((ident, rest))
82 } else {
83 Err(cursor.error(format_args!(
84 "expected identifier, found keyword `{}`",
85 ident,
86 )))
87 }
88 } else {
89 Err(cursor.error("expected identifier"))
90 }
91 })
92 }
93 }
94
95 impl Token for Ident {
peek(cursor: Cursor) -> bool96 fn peek(cursor: Cursor) -> bool {
97 if let Some((ident, _rest)) = cursor.ident() {
98 accept_as_ident(&ident)
99 } else {
100 false
101 }
102 }
103
display() -> &'static str104 fn display() -> &'static str {
105 "identifier"
106 }
107 }
108 }
109