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-rw-r--r--vendor/syn/src/lookahead.rs169
1 files changed, 0 insertions, 169 deletions
diff --git a/vendor/syn/src/lookahead.rs b/vendor/syn/src/lookahead.rs
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index e89a4c7..0000000
--- a/vendor/syn/src/lookahead.rs
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@@ -1,169 +0,0 @@
-use crate::buffer::Cursor;
-use crate::error::{self, Error};
-use crate::sealed::lookahead::Sealed;
-use crate::span::IntoSpans;
-use crate::token::Token;
-use proc_macro2::{Delimiter, Span};
-use std::cell::RefCell;
-
-/// Support for checking the next token in a stream to decide how to parse.
-///
-/// An important advantage over [`ParseStream::peek`] is that here we
-/// automatically construct an appropriate error message based on the token
-/// alternatives that get peeked. If you are producing your own error message,
-/// go ahead and use `ParseStream::peek` instead.
-///
-/// Use [`ParseStream::lookahead1`] to construct this object.
-///
-/// [`ParseStream::peek`]: crate::parse::ParseBuffer::peek
-/// [`ParseStream::lookahead1`]: crate::parse::ParseBuffer::lookahead1
-///
-/// Consuming tokens from the source stream after constructing a lookahead
-/// object does not also advance the lookahead object.
-///
-/// # Example
-///
-/// ```
-/// use syn::{ConstParam, Ident, Lifetime, LifetimeParam, Result, Token, TypeParam};
-/// use syn::parse::{Parse, ParseStream};
-///
-/// // A generic parameter, a single one of the comma-separated elements inside
-/// // angle brackets in:
-/// //
-/// // fn f<T: Clone, 'a, 'b: 'a, const N: usize>() { ... }
-/// //
-/// // On invalid input, lookahead gives us a reasonable error message.
-/// //
-/// // error: expected one of: identifier, lifetime, `const`
-/// // |
-/// // 5 | fn f<!Sized>() {}
-/// // | ^
-/// enum GenericParam {
-/// Type(TypeParam),
-/// Lifetime(LifetimeParam),
-/// Const(ConstParam),
-/// }
-///
-/// impl Parse for GenericParam {
-/// fn parse(input: ParseStream) -> Result<Self> {
-/// let lookahead = input.lookahead1();
-/// if lookahead.peek(Ident) {
-/// input.parse().map(GenericParam::Type)
-/// } else if lookahead.peek(Lifetime) {
-/// input.parse().map(GenericParam::Lifetime)
-/// } else if lookahead.peek(Token![const]) {
-/// input.parse().map(GenericParam::Const)
-/// } else {
-/// Err(lookahead.error())
-/// }
-/// }
-/// }
-/// ```
-pub struct Lookahead1<'a> {
- scope: Span,
- cursor: Cursor<'a>,
- comparisons: RefCell<Vec<&'static str>>,
-}
-
-pub(crate) fn new(scope: Span, cursor: Cursor) -> Lookahead1 {
- Lookahead1 {
- scope,
- cursor,
- comparisons: RefCell::new(Vec::new()),
- }
-}
-
-fn peek_impl(
- lookahead: &Lookahead1,
- peek: fn(Cursor) -> bool,
- display: fn() -> &'static str,
-) -> bool {
- if peek(lookahead.cursor) {
- return true;
- }
- lookahead.comparisons.borrow_mut().push(display());
- false
-}
-
-impl<'a> Lookahead1<'a> {
- /// Looks at the next token in the parse stream to determine whether it
- /// matches the requested type of token.
- ///
- /// # Syntax
- ///
- /// Note that this method does not use turbofish syntax. Pass the peek type
- /// inside of parentheses.
- ///
- /// - `input.peek(Token![struct])`
- /// - `input.peek(Token![==])`
- /// - `input.peek(Ident)`&emsp;*(does not accept keywords)*
- /// - `input.peek(Ident::peek_any)`
- /// - `input.peek(Lifetime)`
- /// - `input.peek(token::Brace)`
- pub fn peek<T: Peek>(&self, token: T) -> bool {
- let _ = token;
- peek_impl(self, T::Token::peek, T::Token::display)
- }
-
- /// Triggers an error at the current position of the parse stream.
- ///
- /// The error message will identify all of the expected token types that
- /// have been peeked against this lookahead instance.
- pub fn error(self) -> Error {
- let comparisons = self.comparisons.borrow();
- match comparisons.len() {
- 0 => {
- if self.cursor.eof() {
- Error::new(self.scope, "unexpected end of input")
- } else {
- Error::new(self.cursor.span(), "unexpected token")
- }
- }
- 1 => {
- let message = format!("expected {}", comparisons[0]);
- error::new_at(self.scope, self.cursor, message)
- }
- 2 => {
- let message = format!("expected {} or {}", comparisons[0], comparisons[1]);
- error::new_at(self.scope, self.cursor, message)
- }
- _ => {
- let join = comparisons.join(", ");
- let message = format!("expected one of: {}", join);
- error::new_at(self.scope, self.cursor, message)
- }
- }
- }
-}
-
-/// Types that can be parsed by looking at just one token.
-///
-/// Use [`ParseStream::peek`] to peek one of these types in a parse stream
-/// without consuming it from the stream.
-///
-/// This trait is sealed and cannot be implemented for types outside of Syn.
-///
-/// [`ParseStream::peek`]: crate::parse::ParseBuffer::peek
-pub trait Peek: Sealed {
- // Not public API.
- #[doc(hidden)]
- type Token: Token;
-}
-
-impl<F: Copy + FnOnce(TokenMarker) -> T, T: Token> Peek for F {
- type Token = T;
-}
-
-pub enum TokenMarker {}
-
-impl<S> IntoSpans<S> for TokenMarker {
- fn into_spans(self) -> S {
- match self {}
- }
-}
-
-pub(crate) fn is_delimiter(cursor: Cursor, delimiter: Delimiter) -> bool {
- cursor.group(delimiter).is_some()
-}
-
-impl<F: Copy + FnOnce(TokenMarker) -> T, T: Token> Sealed for F {}