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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
commit | 36d22d82aa202bb199967e9512281e9a53db42c9 (patch) | |
tree | 105e8c98ddea1c1e4784a60a5a6410fa416be2de /third_party/rust/quote/src/ext.rs | |
parent | Initial commit. (diff) | |
download | firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip |
Adding upstream version 115.7.0esr.upstream/115.7.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/quote/src/ext.rs')
-rw-r--r-- | third_party/rust/quote/src/ext.rs | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/third_party/rust/quote/src/ext.rs b/third_party/rust/quote/src/ext.rs new file mode 100644 index 0000000000..92c2315b18 --- /dev/null +++ b/third_party/rust/quote/src/ext.rs @@ -0,0 +1,110 @@ +use super::ToTokens; +use core::iter; +use proc_macro2::{TokenStream, TokenTree}; + +/// TokenStream extension trait with methods for appending tokens. +/// +/// This trait is sealed and cannot be implemented outside of the `quote` crate. +pub trait TokenStreamExt: private::Sealed { + /// For use by `ToTokens` implementations. + /// + /// Appends the token specified to this list of tokens. + fn append<U>(&mut self, token: U) + where + U: Into<TokenTree>; + + /// For use by `ToTokens` implementations. + /// + /// ``` + /// # use quote::{quote, TokenStreamExt, ToTokens}; + /// # use proc_macro2::TokenStream; + /// # + /// struct X; + /// + /// impl ToTokens for X { + /// fn to_tokens(&self, tokens: &mut TokenStream) { + /// tokens.append_all(&[true, false]); + /// } + /// } + /// + /// let tokens = quote!(#X); + /// assert_eq!(tokens.to_string(), "true false"); + /// ``` + fn append_all<I>(&mut self, iter: I) + where + I: IntoIterator, + I::Item: ToTokens; + + /// For use by `ToTokens` implementations. + /// + /// Appends all of the items in the iterator `I`, separated by the tokens + /// `U`. + fn append_separated<I, U>(&mut self, iter: I, op: U) + where + I: IntoIterator, + I::Item: ToTokens, + U: ToTokens; + + /// For use by `ToTokens` implementations. + /// + /// Appends all tokens in the iterator `I`, appending `U` after each + /// element, including after the last element of the iterator. + fn append_terminated<I, U>(&mut self, iter: I, term: U) + where + I: IntoIterator, + I::Item: ToTokens, + U: ToTokens; +} + +impl TokenStreamExt for TokenStream { + fn append<U>(&mut self, token: U) + where + U: Into<TokenTree>, + { + self.extend(iter::once(token.into())); + } + + fn append_all<I>(&mut self, iter: I) + where + I: IntoIterator, + I::Item: ToTokens, + { + for token in iter { + token.to_tokens(self); + } + } + + fn append_separated<I, U>(&mut self, iter: I, op: U) + where + I: IntoIterator, + I::Item: ToTokens, + U: ToTokens, + { + for (i, token) in iter.into_iter().enumerate() { + if i > 0 { + op.to_tokens(self); + } + token.to_tokens(self); + } + } + + fn append_terminated<I, U>(&mut self, iter: I, term: U) + where + I: IntoIterator, + I::Item: ToTokens, + U: ToTokens, + { + for token in iter { + token.to_tokens(self); + term.to_tokens(self); + } + } +} + +mod private { + use proc_macro2::TokenStream; + + pub trait Sealed {} + + impl Sealed for TokenStream {} +} |