[v2,1/5] rust: macros: add `quote!` macro
Commit Message
From: Gary Guo <gary@garyguo.net>
Add the `quote!` macro for creating `TokenStream`s directly via the
given Rust tokens. It also supports repetitions using iterators.
It will be used by the pin-init API proc-macros to generate code.
Signed-off-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Benno Lossin <y86-dev@protonmail.com>
---
rust/macros/lib.rs | 2 +
rust/macros/quote.rs | 143 +++++++++++++++++++++++++++++++++++++++++++
2 files changed, 145 insertions(+)
create mode 100644 rust/macros/quote.rs
--
2.39.2
@@ -2,6 +2,8 @@
//! Crate for all kernel procedural macros.
+#[macro_use]
+mod quote;
mod concat_idents;
mod helpers;
mod module;
new file mode 100644
@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+use proc_macro::{TokenStream, TokenTree};
+
+pub(crate) trait ToTokens {
+ fn to_tokens(&self, tokens: &mut TokenStream);
+}
+
+impl<T: ToTokens> ToTokens for Option<T> {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ if let Some(v) = self {
+ v.to_tokens(tokens);
+ }
+ }
+}
+
+impl ToTokens for proc_macro::Group {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.extend([TokenTree::from(self.clone())]);
+ }
+}
+
+impl ToTokens for TokenTree {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.extend([self.clone()]);
+ }
+}
+
+impl ToTokens for TokenStream {
+ fn to_tokens(&self, tokens: &mut TokenStream) {
+ tokens.extend(self.clone());
+ }
+}
+
+/// Converts tokens into [`proc_macro::TokenStream`] and performs variable interpolations with
+/// the given span.
+///
+/// This is a similar to the
+/// [`quote_spanned!`](https://docs.rs/quote/latest/quote/macro.quote_spanned.html) macro from the
+/// `quote` crate but provides only just enough functionality needed by the current `macros` crate.
+macro_rules! quote_spanned {
+ ($span:expr => $($tt:tt)*) => {
+ #[allow(clippy::vec_init_then_push)]
+ {
+ let mut tokens = Vec::new();
+ let span = $span;
+ quote_spanned!(@proc tokens span $($tt)*);
+ proc_macro::TokenStream::from_iter(tokens)
+ }};
+ (@proc $v:ident $span:ident) => {};
+ (@proc $v:ident $span:ident #$id:ident $($tt:tt)*) => {
+ let mut ts = proc_macro::TokenStream::new();
+ crate::quote::ToTokens::to_tokens(&$id, &mut ts);
+ $v.extend(ts.into_iter());
+ quote_spanned!(@proc $v $span $($tt)*);
+ };
+ (@proc $v:ident $span:ident #(#$id:ident)* $($tt:tt)*) => {
+ for token in $id {
+ let mut ts = proc_macro::TokenStream::new();
+ crate::quote::ToTokens::to_tokens(&token, &mut ts);
+ $v.extend(ts.into_iter());
+ }
+ quote_spanned!(@proc $v $span $($tt)*);
+ };
+ (@proc $v:ident $span:ident ( $($inner:tt)* ) $($tt:tt)*) => {
+ let mut tokens = Vec::new();
+ quote_spanned!(@proc tokens $span $($inner)*);
+ $v.push(proc_macro::TokenTree::Group(proc_macro::Group::new(
+ proc_macro::Delimiter::Parenthesis,
+ proc_macro::TokenStream::from_iter(tokens)
+ )));
+ quote_spanned!(@proc $v $span $($tt)*);
+ };
+ (@proc $v:ident $span:ident [ $($inner:tt)* ] $($tt:tt)*) => {
+ let mut tokens = Vec::new();
+ quote_spanned!(@proc tokens $span $($inner)*);
+ $v.push(proc_macro::TokenTree::Group(proc_macro::Group::new(
+ proc_macro::Delimiter::Bracket,
+ proc_macro::TokenStream::from_iter(tokens)
+ )));
+ quote_spanned!(@proc $v $span $($tt)*);
+ };
+ (@proc $v:ident $span:ident { $($inner:tt)* } $($tt:tt)*) => {
+ let mut tokens = Vec::new();
+ quote_spanned!(@proc tokens $span $($inner)*);
+ $v.push(proc_macro::TokenTree::Group(proc_macro::Group::new(
+ proc_macro::Delimiter::Brace,
+ proc_macro::TokenStream::from_iter(tokens)
+ )));
+ quote_spanned!(@proc $v $span $($tt)*);
+ };
+ (@proc $v:ident $span:ident :: $($tt:tt)*) => {
+ $v.push(
+ proc_macro::TokenTree::Punct(proc_macro::Punct::new(':', proc_macro::Spacing::Joint))
+ );
+ $v.push(
+ proc_macro::TokenTree::Punct(proc_macro::Punct::new(':', proc_macro::Spacing::Alone))
+ );
+ quote_spanned!(@proc $v $span $($tt)*);
+ };
+ (@proc $v:ident $span:ident : $($tt:tt)*) => {
+ $v.push(
+ proc_macro::TokenTree::Punct(proc_macro::Punct::new(':', proc_macro::Spacing::Alone))
+ );
+ quote_spanned!(@proc $v $span $($tt)*);
+ };
+ (@proc $v:ident $span:ident , $($tt:tt)*) => {
+ $v.push(
+ proc_macro::TokenTree::Punct(proc_macro::Punct::new(',', proc_macro::Spacing::Alone))
+ );
+ quote_spanned!(@proc $v $span $($tt)*);
+ };
+ (@proc $v:ident $span:ident @ $($tt:tt)*) => {
+ $v.push(
+ proc_macro::TokenTree::Punct(proc_macro::Punct::new('@', proc_macro::Spacing::Alone))
+ );
+ quote_spanned!(@proc $v $span $($tt)*);
+ };
+ (@proc $v:ident $span:ident ! $($tt:tt)*) => {
+ $v.push(
+ proc_macro::TokenTree::Punct(proc_macro::Punct::new('!', proc_macro::Spacing::Alone))
+ );
+ quote_spanned!(@proc $v $span $($tt)*);
+ };
+ (@proc $v:ident $span:ident $id:ident $($tt:tt)*) => {
+ $v.push(proc_macro::TokenTree::Ident(proc_macro::Ident::new(stringify!($id), $span)));
+ quote_spanned!(@proc $v $span $($tt)*);
+ };
+}
+
+/// Converts tokens into [`proc_macro::TokenStream`] and performs variable interpolations with
+/// mixed site span ([`Span::mixed_site()`]).
+///
+/// This is a similar to the [`quote!`](https://docs.rs/quote/latest/quote/macro.quote.html) macro
+/// from the `quote` crate but provides only just enough functionality needed by the current
+/// `macros` crate.
+///
+/// [`Span::mixed_site()`]: https://doc.rust-lang.org/proc_macro/struct.Span.html#method.mixed_site
+macro_rules! quote {
+ ($($tt:tt)*) => {
+ quote_spanned!(proc_macro::Span::mixed_site() => $($tt)*)
+ }
+}