vendor/time-macros/src/quote.rs

   1 macro_rules! quote {
   2     () => (::proc_macro::TokenStream::new());
   3     ($($x:tt)*) => {{
   4         let mut ts = ::proc_macro::TokenStream::new();
   5         let ts_mut = &mut ts;
   6         quote_inner!(ts_mut $($x)*);
   7         ts
   8     }};
   9 }
  10
  11 #[cfg(any(feature = "formatting", feature = "parsing"))]
  12 macro_rules! quote_append {
  13     ($ts:ident $($x:tt)*) => {{
  14         quote_inner!($ts $($x)*);
  15     }};
  16 }
  17
  18 macro_rules! quote_group {
  19     ({ $($x:tt)* }) => {
  20         ::proc_macro::TokenTree::Group(::proc_macro::Group::new(
  21             ::proc_macro::Delimiter::Brace,
  22             quote!($($x)*)
  23         ))
  24     };
  25 }
  26
  27 macro_rules! sym {
  28     ($ts:ident $x:tt $y:tt) => {
  29         $ts.extend([
  30             ::proc_macro::TokenTree::from(::proc_macro::Punct::new(
  31                 $x,
  32                 ::proc_macro::Spacing::Joint,
  33             )),
  34             ::proc_macro::TokenTree::from(::proc_macro::Punct::new(
  35                 $y,
  36                 ::proc_macro::Spacing::Alone,
  37             )),
  38         ]);
  39     };
  40     ($ts:ident $x:tt) => {
  41         $ts.extend([::proc_macro::TokenTree::from(::proc_macro::Punct::new(
  42             $x,
  43             ::proc_macro::Spacing::Alone,
  44         ))]);
  45     };
  46 }
  47
  48 macro_rules! quote_inner {
  49     // Base case
  50     ($ts:ident) => {};
  51
  52     // Single or double symbols
  53     ($ts:ident :: $($tail:tt)*) => { sym!($ts ':' ':'); quote_inner!($ts $($tail)*); };
  54     ($ts:ident .. $($tail:tt)*) => { sym!($ts '.' '.'); quote_inner!($ts $($tail)*); };
  55     ($ts:ident : $($tail:tt)*) => { sym!($ts ':'); quote_inner!($ts $($tail)*); };
  56     ($ts:ident = $($tail:tt)*) => { sym!($ts '='); quote_inner!($ts $($tail)*); };
  57     ($ts:ident ; $($tail:tt)*) => { sym!($ts ';'); quote_inner!($ts $($tail)*); };
  58     ($ts:ident , $($tail:tt)*) => { sym!($ts ','); quote_inner!($ts $($tail)*); };
  59     ($ts:ident . $($tail:tt)*) => { sym!($ts '.'); quote_inner!($ts $($tail)*); };
  60     ($ts:ident & $($tail:tt)*) => { sym!($ts '&'); quote_inner!($ts $($tail)*); };
  61     ($ts:ident << $($tail:tt)*) => { sym!($ts '<' '<'); quote_inner!($ts $($tail)*); };
  62     ($ts:ident < $($tail:tt)*) => { sym!($ts '<'); quote_inner!($ts $($tail)*); };
  63     ($ts:ident >> $($tail:tt)*) => { sym!($ts '>' '>'); quote_inner!($ts $($tail)*); };
  64     ($ts:ident > $($tail:tt)*) => { sym!($ts '>'); quote_inner!($ts $($tail)*); };
  65     ($ts:ident -> $($tail:tt)*) => { sym!($ts '-' '>'); quote_inner!($ts $($tail)*); };
  66     ($ts:ident ? $($tail:tt)*) => { sym!($ts '?'); quote_inner!($ts $($tail)*); };
  67     ($ts:ident ! $($tail:tt)*) => { sym!($ts '!'); quote_inner!($ts $($tail)*); };
  68     ($ts:ident | $($tail:tt)*) => { sym!($ts '|'); quote_inner!($ts $($tail)*); };
  69     ($ts:ident * $($tail:tt)*) => { sym!($ts '*'); quote_inner!($ts $($tail)*); };
  70
  71     // Identifier
  72     ($ts:ident $i:ident $($tail:tt)*) => {
  73         $ts.extend([::proc_macro::TokenTree::from(::proc_macro::Ident::new(
  74             &stringify!($i),
  75             ::proc_macro::Span::mixed_site(),
  76         ))]);
  77         quote_inner!($ts $($tail)*);
  78     };
  79
  80     // Literal
  81     ($ts:ident $l:literal $($tail:tt)*) => {
  82         $ts.extend([::proc_macro::TokenTree::from(::proc_macro::Literal::string(&$l))]);
  83         quote_inner!($ts $($tail)*);
  84     };
  85
  86     // Lifetime
  87     ($ts:ident $l:lifetime $($tail:tt)*) => {
  88         $ts.extend([
  89             ::proc_macro::TokenTree::from(
  90                 ::proc_macro::Punct::new('\'', ::proc_macro::Spacing::Joint)
  91             ),
  92             ::proc_macro::TokenTree::from(::proc_macro::Ident::new(
  93                 stringify!($l).trim_start_matches(|c| c == '\''),
  94                 ::proc_macro::Span::mixed_site(),
  95             )),
  96         ]);
  97         quote_inner!($ts $($tail)*);
  98     };
  99
 100     // Groups
 101     ($ts:ident ($($inner:tt)*) $($tail:tt)*) => {
 102         $ts.extend([::proc_macro::TokenTree::Group(::proc_macro::Group::new(
 103             ::proc_macro::Delimiter::Parenthesis,
 104             quote!($($inner)*)
 105         ))]);
 106         quote_inner!($ts $($tail)*);
 107     };
 108     ($ts:ident [$($inner:tt)*] $($tail:tt)*) => {
 109         $ts.extend([::proc_macro::TokenTree::Group(::proc_macro::Group::new(
 110             ::proc_macro::Delimiter::Bracket,
 111             quote!($($inner)*)
 112         ))]);
 113         quote_inner!($ts $($tail)*);
 114     };
 115     ($ts:ident {$($inner:tt)*} $($tail:tt)*) => {
 116         $ts.extend([::proc_macro::TokenTree::Group(::proc_macro::Group::new(
 117             ::proc_macro::Delimiter::Brace,
 118             quote!($($inner)*)
 119         ))]);
 120         quote_inner!($ts $($tail)*);
 121     };
 122
 123     // Interpolated values
 124     // TokenTree by default
 125     ($ts:ident #($e:expr) $($tail:tt)*) => {
 126         $ts.extend([$crate::to_tokens::ToTokenTree::into_token_tree($e)]);
 127         quote_inner!($ts $($tail)*);
 128     };
 129     // Allow a TokenStream by request. It's more expensive, so avoid if possible.
 130     ($ts:ident #S($e:expr) $($tail:tt)*) => {
 131         $crate::to_tokens::ToTokenStream::append_to($e, $ts);
 132         quote_inner!($ts $($tail)*);
 133     };
 134 }