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Add a new trait
proc_macro::ToTokens
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use std::borrow::Cow; | ||
use std::ffi::{CStr, CString}; | ||
use std::rc::Rc; | ||
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use crate::{ConcatTreesHelper, Group, Ident, Literal, Punct, Span, TokenStream, TokenTree}; | ||
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/// Types that can be interpolated inside a [`quote!`] invocation. | ||
/// | ||
/// [`quote!`]: crate::quote! | ||
#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
pub trait ToTokens { | ||
/// Write `self` to the given `TokenStream`. | ||
/// | ||
/// # Example | ||
/// | ||
/// Example implementation for a struct representing Rust paths like | ||
/// `std::cmp::PartialEq`: | ||
/// | ||
/// ``` | ||
/// #![feature(proc_macro_totokens)] | ||
/// | ||
/// use std::iter; | ||
/// use proc_macro::{Spacing, Punct, TokenStream, ToTokens}; | ||
/// | ||
/// pub struct Path { | ||
/// pub global: bool, | ||
/// pub segments: Vec<PathSegment>, | ||
/// } | ||
/// | ||
/// impl ToTokens for Path { | ||
/// fn to_tokens(&self, tokens: &mut TokenStream) { | ||
/// for (i, segment) in self.segments.iter().enumerate() { | ||
/// if i > 0 || self.global { | ||
/// // Double colon `::` | ||
/// tokens.extend(iter::once(Punct::new(':', Spacing::Joint))); | ||
/// tokens.extend(iter::once(Punct::new(':', Spacing::Alone))); | ||
/// } | ||
/// segment.to_tokens(tokens); | ||
/// } | ||
/// } | ||
/// } | ||
/// # | ||
/// # pub struct PathSegment; | ||
/// # | ||
/// # impl ToTokens for PathSegment { | ||
/// # fn to_tokens(&self, tokens: &mut TokenStream) { | ||
/// # unimplemented!() | ||
/// # } | ||
/// # } | ||
/// ``` | ||
fn to_tokens(&self, tokens: &mut TokenStream); | ||
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/// Convert `self` directly into a `TokenStream` object. | ||
/// | ||
/// This method is implicitly implemented using `to_tokens`, and acts as a | ||
/// convenience method for consumers of the `ToTokens` trait. | ||
fn to_token_stream(&self) -> TokenStream { | ||
let mut tokens = TokenStream::new(); | ||
self.to_tokens(&mut tokens); | ||
tokens | ||
} | ||
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/// Convert `self` directly into a `TokenStream` object. | ||
/// | ||
/// This method is implicitly implemented using `to_tokens`, and acts as a | ||
/// convenience method for consumers of the `ToTokens` trait. | ||
fn into_token_stream(self) -> TokenStream | ||
where | ||
Self: Sized, | ||
{ | ||
self.to_token_stream() | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for TokenTree { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
tokens.extend_one(self.clone()); | ||
} | ||
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fn into_token_stream(self) -> TokenStream { | ||
let mut builder = ConcatTreesHelper::new(1); | ||
builder.push(self); | ||
builder.build() | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for TokenStream { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
tokens.extend(self.clone()); | ||
} | ||
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fn into_token_stream(self) -> TokenStream { | ||
self | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for Literal { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
tokens.extend_one(TokenTree::from(self.clone())); | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for Ident { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
tokens.extend_one(TokenTree::from(self.clone())); | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for Punct { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
tokens.extend_one(TokenTree::from(self.clone())); | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for Group { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
tokens.extend_one(TokenTree::from(self.clone())); | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl<T: ToTokens + ?Sized> ToTokens for &T { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
(**self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl<T: ToTokens + ?Sized> ToTokens for &mut T { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
(**self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl<T: ToTokens + ?Sized> ToTokens for Box<T> { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
(**self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl<T: ToTokens + ?Sized> ToTokens for Rc<T> { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
(**self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl<T: ToTokens + ToOwned + ?Sized> ToTokens for Cow<'_, T> { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
(**self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl<T: ToTokens> ToTokens for Option<T> { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
if let Some(t) = self { | ||
t.to_tokens(tokens); | ||
} | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for u8 { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
Literal::u8_suffixed(*self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for u16 { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
Literal::u16_suffixed(*self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for u32 { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
Literal::u32_suffixed(*self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for u64 { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
Literal::u64_suffixed(*self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for u128 { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
Literal::u128_suffixed(*self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for i8 { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
Literal::i8_suffixed(*self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for i16 { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
Literal::i16_suffixed(*self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for i32 { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
Literal::i32_suffixed(*self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for i64 { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
Literal::i64_suffixed(*self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for i128 { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
Literal::i128_suffixed(*self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for f32 { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
Literal::f32_suffixed(*self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for f64 { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
Literal::f64_suffixed(*self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for usize { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
Literal::usize_suffixed(*self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for isize { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
Literal::isize_suffixed(*self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for bool { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
let word = if *self { "true" } else { "false" }; | ||
Ident::new(word, Span::call_site()).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for char { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
Literal::character(*self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for str { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
Literal::string(self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for String { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
Literal::string(self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for CStr { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
Literal::c_string(self).to_tokens(tokens) | ||
} | ||
} | ||
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#[unstable(feature = "proc_macro_totokens", issue = "130977")] | ||
impl ToTokens for CString { | ||
fn to_tokens(&self, tokens: &mut TokenStream) { | ||
Literal::c_string(self).to_tokens(tokens) | ||
} | ||
} |