1 // SPDX-License-Identifier: Apache-2.0 OR MIT 2 3 use proc_macro::{TokenStream, TokenTree}; 4 5 pub(crate) trait ToTokens { 6 fn to_tokens(&self, tokens: &mut TokenStream); 7 } 8 9 impl<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 17 impl ToTokens for proc_macro::Group { 18 fn to_tokens(&self, tokens: &mut TokenStream) { 19 tokens.extend([TokenTree::from(self.clone())]); 20 } 21 } 22 23 impl ToTokens for TokenTree { 24 fn to_tokens(&self, tokens: &mut TokenStream) { 25 tokens.extend([self.clone()]); 26 } 27 } 28 29 impl 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 with 36 /// the given span. 37 /// 38 /// This is a similar to the 39 /// [`quote_spanned!`](https://docs.rs/quote/latest/quote/macro.quote_spanned.html) macro from the 40 /// `quote` crate but provides only just enough functionality needed by the current `macros` crate. 41 macro_rules! quote_spanned { 42 ($span:expr => $($tt:tt)*) => { 43 #[allow(clippy::vec_init_then_push)] 44 { 45 let mut tokens = ::std::vec::Vec::new(); 46 let span = $span; 47 quote_spanned!(@proc tokens span $($tt)*); 48 ::proc_macro::TokenStream::from_iter(tokens) 49 }}; 50 (@proc $v:ident $span:ident) => {}; 51 (@proc $v:ident $span:ident #$id:ident $($tt:tt)*) => { 52 let mut ts = ::proc_macro::TokenStream::new(); 53 $crate::quote::ToTokens::to_tokens(&$id, &mut ts); 54 $v.extend(ts); 55 quote_spanned!(@proc $v $span $($tt)*); 56 }; 57 (@proc $v:ident $span:ident #(#$id:ident)* $($tt:tt)*) => { 58 for token in $id { 59 let mut ts = ::proc_macro::TokenStream::new(); 60 $crate::quote::ToTokens::to_tokens(&token, &mut ts); 61 $v.extend(ts); 62 } 63 quote_spanned!(@proc $v $span $($tt)*); 64 }; 65 (@proc $v:ident $span:ident ( $($inner:tt)* ) $($tt:tt)*) => { 66 let mut tokens = ::std::vec::Vec::new(); 67 quote_spanned!(@proc tokens $span $($inner)*); 68 $v.push(::proc_macro::TokenTree::Group(::proc_macro::Group::new( 69 ::proc_macro::Delimiter::Parenthesis, 70 ::proc_macro::TokenStream::from_iter(tokens) 71 ))); 72 quote_spanned!(@proc $v $span $($tt)*); 73 }; 74 (@proc $v:ident $span:ident [ $($inner:tt)* ] $($tt:tt)*) => { 75 let mut tokens = ::std::vec::Vec::new(); 76 quote_spanned!(@proc tokens $span $($inner)*); 77 $v.push(::proc_macro::TokenTree::Group(::proc_macro::Group::new( 78 ::proc_macro::Delimiter::Bracket, 79 ::proc_macro::TokenStream::from_iter(tokens) 80 ))); 81 quote_spanned!(@proc $v $span $($tt)*); 82 }; 83 (@proc $v:ident $span:ident { $($inner:tt)* } $($tt:tt)*) => { 84 let mut tokens = ::std::vec::Vec::new(); 85 quote_spanned!(@proc tokens $span $($inner)*); 86 $v.push(::proc_macro::TokenTree::Group(::proc_macro::Group::new( 87 ::proc_macro::Delimiter::Brace, 88 ::proc_macro::TokenStream::from_iter(tokens) 89 ))); 90 quote_spanned!(@proc $v $span $($tt)*); 91 }; 92 (@proc $v:ident $span:ident :: $($tt:tt)*) => { 93 $v.push(::proc_macro::TokenTree::Punct( 94 ::proc_macro::Punct::new(':', ::proc_macro::Spacing::Joint) 95 )); 96 $v.push(::proc_macro::TokenTree::Punct( 97 ::proc_macro::Punct::new(':', ::proc_macro::Spacing::Alone) 98 )); 99 quote_spanned!(@proc $v $span $($tt)*); 100 }; 101 (@proc $v:ident $span:ident : $($tt:tt)*) => { 102 $v.push(::proc_macro::TokenTree::Punct( 103 ::proc_macro::Punct::new(':', ::proc_macro::Spacing::Alone) 104 )); 105 quote_spanned!(@proc $v $span $($tt)*); 106 }; 107 (@proc $v:ident $span:ident , $($tt:tt)*) => { 108 $v.push(::proc_macro::TokenTree::Punct( 109 ::proc_macro::Punct::new(',', ::proc_macro::Spacing::Alone) 110 )); 111 quote_spanned!(@proc $v $span $($tt)*); 112 }; 113 (@proc $v:ident $span:ident @ $($tt:tt)*) => { 114 $v.push(::proc_macro::TokenTree::Punct( 115 ::proc_macro::Punct::new('@', ::proc_macro::Spacing::Alone) 116 )); 117 quote_spanned!(@proc $v $span $($tt)*); 118 }; 119 (@proc $v:ident $span:ident ! $($tt:tt)*) => { 120 $v.push(::proc_macro::TokenTree::Punct( 121 ::proc_macro::Punct::new('!', ::proc_macro::Spacing::Alone) 122 )); 123 quote_spanned!(@proc $v $span $($tt)*); 124 }; 125 (@proc $v:ident $span:ident $id:ident $($tt:tt)*) => { 126 $v.push(::proc_macro::TokenTree::Ident(::proc_macro::Ident::new(stringify!($id), $span))); 127 quote_spanned!(@proc $v $span $($tt)*); 128 }; 129 } 130 131 /// Converts tokens into [`proc_macro::TokenStream`] and performs variable interpolations with 132 /// mixed site span ([`Span::mixed_site()`]). 133 /// 134 /// This is a similar to the [`quote!`](https://docs.rs/quote/latest/quote/macro.quote.html) macro 135 /// from the `quote` crate but provides only just enough functionality needed by the current 136 /// `macros` crate. 137 /// 138 /// [`Span::mixed_site()`]: https://doc.rust-lang.org/proc_macro/struct.Span.html#method.mixed_site 139 macro_rules! quote { 140 ($($tt:tt)*) => { 141 quote_spanned!(::proc_macro::Span::mixed_site() => $($tt)*) 142 } 143 } 144