Skip to content

Commit 7be29e9

Browse files
workingjubileeworkingjubilee
authored
Rollup merge of rust-lang#131441 - SpriteOvO:proc-macro-to-tokens-trait, r=dtolnay
Add a new trait `proc_macro::ToTokens` Tracking issue rust-lang#130977 This PR adds a new trait `ToTokens`, implemented for types that can be interpolated inside a `quote!` invocation. ```rust impl ToTokens for TokenTree impl ToTokens for TokenStream impl ToTokens for Literal impl ToTokens for Ident impl ToTokens for Punct impl ToTokens for Group impl<T: ToTokens + ?Sized> ToTokens for &T impl<T: ToTokens + ?Sized> ToTokens for &mut T impl<T: ToTokens + ?Sized> ToTokens for Box<T> impl<T: ToTokens + ?Sized> ToTokens for Rc<T> impl<T: ToTokens + ToOwned + ?Sized> ToTokens for Cow<'_, T> impl<T: ToTokens> ToTokens for Option<T> impl ToTokens for u{8,16,32,64,128} impl ToTokens for i{8,16,32,64,128} impl ToTokens for f{32,64} impl ToTokens for {u,i}size impl ToTokens for bool impl ToTokens for char impl ToTokens for str impl ToTokens for String impl ToTokens for CStr impl ToTokens for CString ``` ~This PR also implements the migration mentioned in the tracking issue, replacing `Extend<Token{Tree,Stream}>` with `Extend<T: ToTokens>`, and replacing `FromIterator<Token{Tree,Stream}>` with `FromIterator<T: ToTokens>`.~ **UPDATE**: Reverted. ```diff -impl FromIterator<TokenTree> for TokenStream -impl FromIterator<TokenStream> for TokenStream +impl<T: ToTokens> FromIterator<T> for TokenStream -impl Extend<TokenTree> for TokenStream -impl Extend<TokenStream> for TokenStream +impl<T: ToTokens> Extend<T> for TokenStream ``` I'm going to leave some comments in the review where I'm unsure and concerned. r? ``@dtolnay`` CC ``@tgross35``
2 parents 8cdb783 + 80f0aa3 commit 7be29e9

File tree

2 files changed

+314
-0
lines changed

2 files changed

+314
-0
lines changed

‎proc_macro/src/lib.rs‎

Lines changed: 4 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -32,6 +32,7 @@
3232
#![feature(restricted_std)]
3333
#![feature(rustc_attrs)]
3434
#![feature(min_specialization)]
35+
#![feature(extend_one)]
3536
#![recursion_limit = "256"]
3637
#![allow(internal_features)]
3738
#![deny(ffi_unwind_calls)]
@@ -43,6 +44,7 @@ pub mod bridge;
4344

4445
mod diagnostic;
4546
mod escape;
47+
mod to_tokens;
4648

4749
use std::ffi::CStr;
4850
use std::ops::{Range, RangeBounds};
@@ -52,6 +54,8 @@ use std::{error, fmt};
5254

5355
#[unstable(feature = "proc_macro_diagnostic", issue = "54140")]
5456
pub use diagnostic::{Diagnostic, Level, MultiSpan};
57+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
58+
pub use to_tokens::ToTokens;
5559

5660
use crate::escape::{EscapeOptions, escape_bytes};
5761

‎proc_macro/src/to_tokens.rs‎

Lines changed: 310 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,310 @@
1+
use std::borrow::Cow;
2+
use std::ffi::{CStr, CString};
3+
use std::rc::Rc;
4+
5+
use crate::{ConcatTreesHelper, Group, Ident, Literal, Punct, Span, TokenStream, TokenTree};
6+
7+
/// Types that can be interpolated inside a [`quote!`] invocation.
8+
///
9+
/// [`quote!`]: crate::quote!
10+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
11+
pub trait ToTokens {
12+
/// Write `self` to the given `TokenStream`.
13+
///
14+
/// # Example
15+
///
16+
/// Example implementation for a struct representing Rust paths like
17+
/// `std::cmp::PartialEq`:
18+
///
19+
/// ```
20+
/// #![feature(proc_macro_totokens)]
21+
///
22+
/// use std::iter;
23+
/// use proc_macro::{Spacing, Punct, TokenStream, TokenTree, ToTokens};
24+
///
25+
/// pub struct Path {
26+
/// pub global: bool,
27+
/// pub segments: Vec<PathSegment>,
28+
/// }
29+
///
30+
/// impl ToTokens for Path {
31+
/// fn to_tokens(&self, tokens: &mut TokenStream) {
32+
/// for (i, segment) in self.segments.iter().enumerate() {
33+
/// if i > 0 || self.global {
34+
/// // Double colon `::`
35+
/// tokens.extend(iter::once(TokenTree::from(Punct::new(':', Spacing::Joint))));
36+
/// tokens.extend(iter::once(TokenTree::from(Punct::new(':', Spacing::Alone))));
37+
/// }
38+
/// segment.to_tokens(tokens);
39+
/// }
40+
/// }
41+
/// }
42+
/// #
43+
/// # pub struct PathSegment;
44+
/// #
45+
/// # impl ToTokens for PathSegment {
46+
/// # fn to_tokens(&self, tokens: &mut TokenStream) {
47+
/// # unimplemented!()
48+
/// # }
49+
/// # }
50+
/// ```
51+
fn to_tokens(&self, tokens: &mut TokenStream);
52+
53+
/// Convert `self` directly into a `TokenStream` object.
54+
///
55+
/// This method is implicitly implemented using `to_tokens`, and acts as a
56+
/// convenience method for consumers of the `ToTokens` trait.
57+
fn to_token_stream(&self) -> TokenStream {
58+
let mut tokens = TokenStream::new();
59+
self.to_tokens(&mut tokens);
60+
tokens
61+
}
62+
63+
/// Convert `self` directly into a `TokenStream` object.
64+
///
65+
/// This method is implicitly implemented using `to_tokens`, and acts as a
66+
/// convenience method for consumers of the `ToTokens` trait.
67+
fn into_token_stream(self) -> TokenStream
68+
where
69+
Self: Sized,
70+
{
71+
self.to_token_stream()
72+
}
73+
}
74+
75+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
76+
impl ToTokens for TokenTree {
77+
fn to_tokens(&self, tokens: &mut TokenStream) {
78+
tokens.extend_one(self.clone());
79+
}
80+
81+
fn into_token_stream(self) -> TokenStream {
82+
let mut builder = ConcatTreesHelper::new(1);
83+
builder.push(self);
84+
builder.build()
85+
}
86+
}
87+
88+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
89+
impl ToTokens for TokenStream {
90+
fn to_tokens(&self, tokens: &mut TokenStream) {
91+
tokens.extend(self.clone());
92+
}
93+
94+
fn into_token_stream(self) -> TokenStream {
95+
self
96+
}
97+
}
98+
99+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
100+
impl ToTokens for Literal {
101+
fn to_tokens(&self, tokens: &mut TokenStream) {
102+
tokens.extend_one(TokenTree::from(self.clone()));
103+
}
104+
}
105+
106+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
107+
impl ToTokens for Ident {
108+
fn to_tokens(&self, tokens: &mut TokenStream) {
109+
tokens.extend_one(TokenTree::from(self.clone()));
110+
}
111+
}
112+
113+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
114+
impl ToTokens for Punct {
115+
fn to_tokens(&self, tokens: &mut TokenStream) {
116+
tokens.extend_one(TokenTree::from(self.clone()));
117+
}
118+
}
119+
120+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
121+
impl ToTokens for Group {
122+
fn to_tokens(&self, tokens: &mut TokenStream) {
123+
tokens.extend_one(TokenTree::from(self.clone()));
124+
}
125+
}
126+
127+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
128+
impl<T: ToTokens + ?Sized> ToTokens for &T {
129+
fn to_tokens(&self, tokens: &mut TokenStream) {
130+
(**self).to_tokens(tokens)
131+
}
132+
}
133+
134+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
135+
impl<T: ToTokens + ?Sized> ToTokens for &mut T {
136+
fn to_tokens(&self, tokens: &mut TokenStream) {
137+
(**self).to_tokens(tokens)
138+
}
139+
}
140+
141+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
142+
impl<T: ToTokens + ?Sized> ToTokens for Box<T> {
143+
fn to_tokens(&self, tokens: &mut TokenStream) {
144+
(**self).to_tokens(tokens)
145+
}
146+
}
147+
148+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
149+
impl<T: ToTokens + ?Sized> ToTokens for Rc<T> {
150+
fn to_tokens(&self, tokens: &mut TokenStream) {
151+
(**self).to_tokens(tokens)
152+
}
153+
}
154+
155+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
156+
impl<T: ToTokens + ToOwned + ?Sized> ToTokens for Cow<'_, T> {
157+
fn to_tokens(&self, tokens: &mut TokenStream) {
158+
(**self).to_tokens(tokens)
159+
}
160+
}
161+
162+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
163+
impl<T: ToTokens> ToTokens for Option<T> {
164+
fn to_tokens(&self, tokens: &mut TokenStream) {
165+
if let Some(t) = self {
166+
t.to_tokens(tokens);
167+
}
168+
}
169+
}
170+
171+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
172+
impl ToTokens for u8 {
173+
fn to_tokens(&self, tokens: &mut TokenStream) {
174+
Literal::u8_suffixed(*self).to_tokens(tokens)
175+
}
176+
}
177+
178+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
179+
impl ToTokens for u16 {
180+
fn to_tokens(&self, tokens: &mut TokenStream) {
181+
Literal::u16_suffixed(*self).to_tokens(tokens)
182+
}
183+
}
184+
185+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
186+
impl ToTokens for u32 {
187+
fn to_tokens(&self, tokens: &mut TokenStream) {
188+
Literal::u32_suffixed(*self).to_tokens(tokens)
189+
}
190+
}
191+
192+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
193+
impl ToTokens for u64 {
194+
fn to_tokens(&self, tokens: &mut TokenStream) {
195+
Literal::u64_suffixed(*self).to_tokens(tokens)
196+
}
197+
}
198+
199+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
200+
impl ToTokens for u128 {
201+
fn to_tokens(&self, tokens: &mut TokenStream) {
202+
Literal::u128_suffixed(*self).to_tokens(tokens)
203+
}
204+
}
205+
206+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
207+
impl ToTokens for i8 {
208+
fn to_tokens(&self, tokens: &mut TokenStream) {
209+
Literal::i8_suffixed(*self).to_tokens(tokens)
210+
}
211+
}
212+
213+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
214+
impl ToTokens for i16 {
215+
fn to_tokens(&self, tokens: &mut TokenStream) {
216+
Literal::i16_suffixed(*self).to_tokens(tokens)
217+
}
218+
}
219+
220+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
221+
impl ToTokens for i32 {
222+
fn to_tokens(&self, tokens: &mut TokenStream) {
223+
Literal::i32_suffixed(*self).to_tokens(tokens)
224+
}
225+
}
226+
227+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
228+
impl ToTokens for i64 {
229+
fn to_tokens(&self, tokens: &mut TokenStream) {
230+
Literal::i64_suffixed(*self).to_tokens(tokens)
231+
}
232+
}
233+
234+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
235+
impl ToTokens for i128 {
236+
fn to_tokens(&self, tokens: &mut TokenStream) {
237+
Literal::i128_suffixed(*self).to_tokens(tokens)
238+
}
239+
}
240+
241+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
242+
impl ToTokens for f32 {
243+
fn to_tokens(&self, tokens: &mut TokenStream) {
244+
Literal::f32_suffixed(*self).to_tokens(tokens)
245+
}
246+
}
247+
248+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
249+
impl ToTokens for f64 {
250+
fn to_tokens(&self, tokens: &mut TokenStream) {
251+
Literal::f64_suffixed(*self).to_tokens(tokens)
252+
}
253+
}
254+
255+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
256+
impl ToTokens for usize {
257+
fn to_tokens(&self, tokens: &mut TokenStream) {
258+
Literal::usize_suffixed(*self).to_tokens(tokens)
259+
}
260+
}
261+
262+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
263+
impl ToTokens for isize {
264+
fn to_tokens(&self, tokens: &mut TokenStream) {
265+
Literal::isize_suffixed(*self).to_tokens(tokens)
266+
}
267+
}
268+
269+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
270+
impl ToTokens for bool {
271+
fn to_tokens(&self, tokens: &mut TokenStream) {
272+
let word = if *self { "true" } else { "false" };
273+
Ident::new(word, Span::call_site()).to_tokens(tokens)
274+
}
275+
}
276+
277+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
278+
impl ToTokens for char {
279+
fn to_tokens(&self, tokens: &mut TokenStream) {
280+
Literal::character(*self).to_tokens(tokens)
281+
}
282+
}
283+
284+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
285+
impl ToTokens for str {
286+
fn to_tokens(&self, tokens: &mut TokenStream) {
287+
Literal::string(self).to_tokens(tokens)
288+
}
289+
}
290+
291+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
292+
impl ToTokens for String {
293+
fn to_tokens(&self, tokens: &mut TokenStream) {
294+
Literal::string(self).to_tokens(tokens)
295+
}
296+
}
297+
298+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
299+
impl ToTokens for CStr {
300+
fn to_tokens(&self, tokens: &mut TokenStream) {
301+
Literal::c_string(self).to_tokens(tokens)
302+
}
303+
}
304+
305+
#[unstable(feature = "proc_macro_totokens", issue = "130977")]
306+
impl ToTokens for CString {
307+
fn to_tokens(&self, tokens: &mut TokenStream) {
308+
Literal::c_string(self).to_tokens(tokens)
309+
}
310+
}

0 commit comments

Comments
 (0)