113 lines
2.7 KiB
Rust
113 lines
2.7 KiB
Rust
use super::ToTokens;
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use std::iter;
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use proc_macro2::{TokenStream, TokenTree};
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/// TokenStream extension trait with methods for appending tokens.
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///
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/// This trait is sealed and cannot be implemented outside of the `quote` crate.
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pub trait TokenStreamExt: private::Sealed {
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/// For use by `ToTokens` implementations.
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///
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/// Appends the token specified to this list of tokens.
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fn append<U>(&mut self, token: U)
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where
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U: Into<TokenTree>;
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/// For use by `ToTokens` implementations.
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///
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/// ```
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/// # use quote::{quote, TokenStreamExt, ToTokens};
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/// # use proc_macro2::TokenStream;
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/// #
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/// struct X;
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///
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/// impl ToTokens for X {
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/// fn to_tokens(&self, tokens: &mut TokenStream) {
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/// tokens.append_all(&[true, false]);
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/// }
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/// }
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///
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/// let tokens = quote!(#X);
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/// assert_eq!(tokens.to_string(), "true false");
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/// ```
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fn append_all<I>(&mut self, iter: I)
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where
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I: IntoIterator,
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I::Item: ToTokens;
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/// For use by `ToTokens` implementations.
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///
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/// Appends all of the items in the iterator `I`, separated by the tokens
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/// `U`.
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fn append_separated<I, U>(&mut self, iter: I, op: U)
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where
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I: IntoIterator,
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I::Item: ToTokens,
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U: ToTokens;
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/// For use by `ToTokens` implementations.
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///
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/// Appends all tokens in the iterator `I`, appending `U` after each
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/// element, including after the last element of the iterator.
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fn append_terminated<I, U>(&mut self, iter: I, term: U)
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where
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I: IntoIterator,
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I::Item: ToTokens,
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U: ToTokens;
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}
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impl TokenStreamExt for TokenStream {
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fn append<U>(&mut self, token: U)
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where
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U: Into<TokenTree>,
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{
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self.extend(iter::once(token.into()));
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}
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fn append_all<I>(&mut self, iter: I)
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where
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I: IntoIterator,
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I::Item: ToTokens,
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{
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for token in iter {
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token.to_tokens(self);
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}
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}
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fn append_separated<I, U>(&mut self, iter: I, op: U)
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where
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I: IntoIterator,
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I::Item: ToTokens,
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U: ToTokens,
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{
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for (i, token) in iter.into_iter().enumerate() {
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if i > 0 {
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op.to_tokens(self);
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}
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token.to_tokens(self);
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}
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}
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fn append_terminated<I, U>(&mut self, iter: I, term: U)
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where
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I: IntoIterator,
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I::Item: ToTokens,
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U: ToTokens,
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{
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for token in iter {
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token.to_tokens(self);
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term.to_tokens(self);
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}
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}
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}
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mod private {
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use proc_macro2::TokenStream;
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pub trait Sealed {}
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impl Sealed for TokenStream {}
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}
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