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