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-rw-r--r--third_party/rust/syn/src/custom_keyword.rs253
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diff --git a/third_party/rust/syn/src/custom_keyword.rs b/third_party/rust/syn/src/custom_keyword.rs
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+/// Define a type that supports parsing and printing a given identifier as if it
+/// were a keyword.
+///
+/// # Usage
+///
+/// As a convention, it is recommended that this macro be invoked within a
+/// module called `kw` or `keyword` and that the resulting parser be invoked
+/// with a `kw::` or `keyword::` prefix.
+///
+/// ```
+/// mod kw {
+/// syn::custom_keyword!(whatever);
+/// }
+/// ```
+///
+/// The generated syntax tree node supports the following operations just like
+/// any built-in keyword token.
+///
+/// - [Peeking] — `input.peek(kw::whatever)`
+///
+/// - [Parsing] — `input.parse::<kw::whatever>()?`
+///
+/// - [Printing] — `quote!( ... #whatever_token ... )`
+///
+/// - Construction from a [`Span`] — `let whatever_token = kw::whatever(sp)`
+///
+/// - Field access to its span — `let sp = whatever_token.span`
+///
+/// [Peeking]: crate::parse::ParseBuffer::peek
+/// [Parsing]: crate::parse::ParseBuffer::parse
+/// [Printing]: quote::ToTokens
+/// [`Span`]: proc_macro2::Span
+///
+/// # Example
+///
+/// This example parses input that looks like `bool = true` or `str = "value"`.
+/// The key must be either the identifier `bool` or the identifier `str`. If
+/// `bool`, the value may be either `true` or `false`. If `str`, the value may
+/// be any string literal.
+///
+/// The symbols `bool` and `str` are not reserved keywords in Rust so these are
+/// not considered keywords in the `syn::token` module. Like any other
+/// identifier that is not a keyword, these can be declared as custom keywords
+/// by crates that need to use them as such.
+///
+/// ```
+/// use syn::{LitBool, LitStr, Result, Token};
+/// use syn::parse::{Parse, ParseStream};
+///
+/// mod kw {
+/// syn::custom_keyword!(bool);
+/// syn::custom_keyword!(str);
+/// }
+///
+/// enum Argument {
+/// Bool {
+/// bool_token: kw::bool,
+/// eq_token: Token![=],
+/// value: LitBool,
+/// },
+/// Str {
+/// str_token: kw::str,
+/// eq_token: Token![=],
+/// value: LitStr,
+/// },
+/// }
+///
+/// impl Parse for Argument {
+/// fn parse(input: ParseStream) -> Result<Self> {
+/// let lookahead = input.lookahead1();
+/// if lookahead.peek(kw::bool) {
+/// Ok(Argument::Bool {
+/// bool_token: input.parse::<kw::bool>()?,
+/// eq_token: input.parse()?,
+/// value: input.parse()?,
+/// })
+/// } else if lookahead.peek(kw::str) {
+/// Ok(Argument::Str {
+/// str_token: input.parse::<kw::str>()?,
+/// eq_token: input.parse()?,
+/// value: input.parse()?,
+/// })
+/// } else {
+/// Err(lookahead.error())
+/// }
+/// }
+/// }
+/// ```
+#[macro_export]
+macro_rules! custom_keyword {
+ ($ident:ident) => {
+ #[allow(non_camel_case_types)]
+ pub struct $ident {
+ pub span: $crate::__private::Span,
+ }
+
+ #[doc(hidden)]
+ #[allow(dead_code, non_snake_case)]
+ pub fn $ident<__S: $crate::__private::IntoSpans<[$crate::__private::Span; 1]>>(
+ span: __S,
+ ) -> $ident {
+ $ident {
+ span: $crate::__private::IntoSpans::into_spans(span)[0],
+ }
+ }
+
+ impl $crate::__private::Default for $ident {
+ fn default() -> Self {
+ $ident {
+ span: $crate::__private::Span::call_site(),
+ }
+ }
+ }
+
+ $crate::impl_parse_for_custom_keyword!($ident);
+ $crate::impl_to_tokens_for_custom_keyword!($ident);
+ $crate::impl_clone_for_custom_keyword!($ident);
+ $crate::impl_extra_traits_for_custom_keyword!($ident);
+ };
+}
+
+// Not public API.
+#[cfg(feature = "parsing")]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! impl_parse_for_custom_keyword {
+ ($ident:ident) => {
+ // For peek.
+ impl $crate::token::CustomToken for $ident {
+ fn peek(cursor: $crate::buffer::Cursor) -> $crate::__private::bool {
+ if let $crate::__private::Some((ident, _rest)) = cursor.ident() {
+ ident == stringify!($ident)
+ } else {
+ false
+ }
+ }
+
+ fn display() -> &'static $crate::__private::str {
+ concat!("`", stringify!($ident), "`")
+ }
+ }
+
+ impl $crate::parse::Parse for $ident {
+ fn parse(input: $crate::parse::ParseStream) -> $crate::parse::Result<$ident> {
+ input.step(|cursor| {
+ if let $crate::__private::Some((ident, rest)) = cursor.ident() {
+ if ident == stringify!($ident) {
+ return $crate::__private::Ok(($ident { span: ident.span() }, rest));
+ }
+ }
+ $crate::__private::Err(cursor.error(concat!(
+ "expected `",
+ stringify!($ident),
+ "`"
+ )))
+ })
+ }
+ }
+ };
+}
+
+// Not public API.
+#[cfg(not(feature = "parsing"))]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! impl_parse_for_custom_keyword {
+ ($ident:ident) => {};
+}
+
+// Not public API.
+#[cfg(feature = "printing")]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! impl_to_tokens_for_custom_keyword {
+ ($ident:ident) => {
+ impl $crate::__private::ToTokens for $ident {
+ fn to_tokens(&self, tokens: &mut $crate::__private::TokenStream2) {
+ let ident = $crate::Ident::new(stringify!($ident), self.span);
+ $crate::__private::TokenStreamExt::append(tokens, ident);
+ }
+ }
+ };
+}
+
+// Not public API.
+#[cfg(not(feature = "printing"))]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! impl_to_tokens_for_custom_keyword {
+ ($ident:ident) => {};
+}
+
+// Not public API.
+#[cfg(feature = "clone-impls")]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! impl_clone_for_custom_keyword {
+ ($ident:ident) => {
+ impl $crate::__private::Copy for $ident {}
+
+ #[allow(clippy::expl_impl_clone_on_copy)]
+ impl $crate::__private::Clone for $ident {
+ fn clone(&self) -> Self {
+ *self
+ }
+ }
+ };
+}
+
+// Not public API.
+#[cfg(not(feature = "clone-impls"))]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! impl_clone_for_custom_keyword {
+ ($ident:ident) => {};
+}
+
+// Not public API.
+#[cfg(feature = "extra-traits")]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! impl_extra_traits_for_custom_keyword {
+ ($ident:ident) => {
+ impl $crate::__private::Debug for $ident {
+ fn fmt(&self, f: &mut $crate::__private::Formatter) -> $crate::__private::fmt::Result {
+ $crate::__private::Formatter::write_str(
+ f,
+ concat!("Keyword [", stringify!($ident), "]"),
+ )
+ }
+ }
+
+ impl $crate::__private::Eq for $ident {}
+
+ impl $crate::__private::PartialEq for $ident {
+ fn eq(&self, _other: &Self) -> $crate::__private::bool {
+ true
+ }
+ }
+
+ impl $crate::__private::Hash for $ident {
+ fn hash<__H: $crate::__private::Hasher>(&self, _state: &mut __H) {}
+ }
+ };
+}
+
+// Not public API.
+#[cfg(not(feature = "extra-traits"))]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! impl_extra_traits_for_custom_keyword {
+ ($ident:ident) => {};
+}