158 lines · rust
1// SPDX-License-Identifier: Apache-2.0 OR MIT2 3use proc_macro::{TokenStream, TokenTree};4 5pub(crate) trait ToTokens {6 fn to_tokens(&self, tokens: &mut TokenStream);7}8 9impl<T: ToTokens> ToTokens for Option<T> {10 fn to_tokens(&self, tokens: &mut TokenStream) {11 if let Some(v) = self {12 v.to_tokens(tokens);13 }14 }15}16 17impl ToTokens for proc_macro::Group {18 fn to_tokens(&self, tokens: &mut TokenStream) {19 tokens.extend([TokenTree::from(self.clone())]);20 }21}22 23impl ToTokens for TokenTree {24 fn to_tokens(&self, tokens: &mut TokenStream) {25 tokens.extend([self.clone()]);26 }27}28 29impl ToTokens for TokenStream {30 fn to_tokens(&self, tokens: &mut TokenStream) {31 tokens.extend(self.clone());32 }33}34 35/// Converts tokens into [`proc_macro::TokenStream`] and performs variable interpolations with36/// the given span.37///38/// This is a similar to the39/// [`quote_spanned!`](https://docs.rs/quote/latest/quote/macro.quote_spanned.html) macro from the40/// `quote` crate but provides only just enough functionality needed by the current `macros` crate.41macro_rules! quote_spanned {42 ($span:expr => $($tt:tt)*) => {{43 let mut tokens;44 #[allow(clippy::vec_init_then_push)]45 {46 tokens = ::std::vec::Vec::new();47 let span = $span;48 quote_spanned!(@proc tokens span $($tt)*);49 }50 ::proc_macro::TokenStream::from_iter(tokens)51 }};52 (@proc $v:ident $span:ident) => {};53 (@proc $v:ident $span:ident #$id:ident $($tt:tt)*) => {54 let mut ts = ::proc_macro::TokenStream::new();55 $crate::quote::ToTokens::to_tokens(&$id, &mut ts);56 $v.extend(ts);57 quote_spanned!(@proc $v $span $($tt)*);58 };59 (@proc $v:ident $span:ident #(#$id:ident)* $($tt:tt)*) => {60 for token in $id {61 let mut ts = ::proc_macro::TokenStream::new();62 $crate::quote::ToTokens::to_tokens(&token, &mut ts);63 $v.extend(ts);64 }65 quote_spanned!(@proc $v $span $($tt)*);66 };67 (@proc $v:ident $span:ident ( $($inner:tt)* ) $($tt:tt)*) => {68 let mut tokens = ::std::vec::Vec::new();69 quote_spanned!(@proc tokens $span $($inner)*);70 $v.push(::proc_macro::TokenTree::Group(::proc_macro::Group::new(71 ::proc_macro::Delimiter::Parenthesis,72 ::proc_macro::TokenStream::from_iter(tokens)73 )));74 quote_spanned!(@proc $v $span $($tt)*);75 };76 (@proc $v:ident $span:ident [ $($inner:tt)* ] $($tt:tt)*) => {77 let mut tokens = ::std::vec::Vec::new();78 quote_spanned!(@proc tokens $span $($inner)*);79 $v.push(::proc_macro::TokenTree::Group(::proc_macro::Group::new(80 ::proc_macro::Delimiter::Bracket,81 ::proc_macro::TokenStream::from_iter(tokens)82 )));83 quote_spanned!(@proc $v $span $($tt)*);84 };85 (@proc $v:ident $span:ident { $($inner:tt)* } $($tt:tt)*) => {86 let mut tokens = ::std::vec::Vec::new();87 quote_spanned!(@proc tokens $span $($inner)*);88 $v.push(::proc_macro::TokenTree::Group(::proc_macro::Group::new(89 ::proc_macro::Delimiter::Brace,90 ::proc_macro::TokenStream::from_iter(tokens)91 )));92 quote_spanned!(@proc $v $span $($tt)*);93 };94 (@proc $v:ident $span:ident :: $($tt:tt)*) => {95 $v.push(::proc_macro::TokenTree::Punct(96 ::proc_macro::Punct::new(':', ::proc_macro::Spacing::Joint)97 ));98 $v.push(::proc_macro::TokenTree::Punct(99 ::proc_macro::Punct::new(':', ::proc_macro::Spacing::Alone)100 ));101 quote_spanned!(@proc $v $span $($tt)*);102 };103 (@proc $v:ident $span:ident : $($tt:tt)*) => {104 $v.push(::proc_macro::TokenTree::Punct(105 ::proc_macro::Punct::new(':', ::proc_macro::Spacing::Alone)106 ));107 quote_spanned!(@proc $v $span $($tt)*);108 };109 (@proc $v:ident $span:ident , $($tt:tt)*) => {110 $v.push(::proc_macro::TokenTree::Punct(111 ::proc_macro::Punct::new(',', ::proc_macro::Spacing::Alone)112 ));113 quote_spanned!(@proc $v $span $($tt)*);114 };115 (@proc $v:ident $span:ident @ $($tt:tt)*) => {116 $v.push(::proc_macro::TokenTree::Punct(117 ::proc_macro::Punct::new('@', ::proc_macro::Spacing::Alone)118 ));119 quote_spanned!(@proc $v $span $($tt)*);120 };121 (@proc $v:ident $span:ident ! $($tt:tt)*) => {122 $v.push(::proc_macro::TokenTree::Punct(123 ::proc_macro::Punct::new('!', ::proc_macro::Spacing::Alone)124 ));125 quote_spanned!(@proc $v $span $($tt)*);126 };127 (@proc $v:ident $span:ident ; $($tt:tt)*) => {128 $v.push(::proc_macro::TokenTree::Punct(129 ::proc_macro::Punct::new(';', ::proc_macro::Spacing::Alone)130 ));131 quote_spanned!(@proc $v $span $($tt)*);132 };133 (@proc $v:ident $span:ident + $($tt:tt)*) => {134 $v.push(::proc_macro::TokenTree::Punct(135 ::proc_macro::Punct::new('+', ::proc_macro::Spacing::Alone)136 ));137 quote_spanned!(@proc $v $span $($tt)*);138 };139 (@proc $v:ident $span:ident $id:ident $($tt:tt)*) => {140 $v.push(::proc_macro::TokenTree::Ident(::proc_macro::Ident::new(stringify!($id), $span)));141 quote_spanned!(@proc $v $span $($tt)*);142 };143}144 145/// Converts tokens into [`proc_macro::TokenStream`] and performs variable interpolations with146/// mixed site span ([`Span::mixed_site()`]).147///148/// This is a similar to the [`quote!`](https://docs.rs/quote/latest/quote/macro.quote.html) macro149/// from the `quote` crate but provides only just enough functionality needed by the current150/// `macros` crate.151///152/// [`Span::mixed_site()`]: https://doc.rust-lang.org/proc_macro/struct.Span.html#method.mixed_site153macro_rules! quote {154 ($($tt:tt)*) => {155 quote_spanned!(::proc_macro::Span::mixed_site() => $($tt)*)156 }157}158