time_macros/
quote.rs

1macro_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"))]
12macro_rules! quote_append {
13    ($ts:ident $($x:tt)*) => {{
14        quote_inner!($ts $($x)*);
15    }};
16}
17
18macro_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
27macro_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            $x,
43            ::proc_macro::Spacing::Alone,
44        ))]);
45    };
46}
47
48#[allow(unused_macro_rules)] // Varies by feature flag combination.
49macro_rules! quote_inner {
50    // Base case
51    ($ts:ident) => {};
52
53    // Single or double symbols
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 0 $($tail:tt)*) => {
82        $ts.extend([::proc_macro::TokenTree::from(::proc_macro::Literal::usize_unsuffixed(0))]);
83        quote_inner!($ts $($tail)*);
84    };
85    ($ts:ident $l:literal $($tail:tt)*) => {
86        $ts.extend([::proc_macro::TokenTree::from(::proc_macro::Literal::string(&$l))]);
87        quote_inner!($ts $($tail)*);
88    };
89
90    // Lifetime
91    ($ts:ident $l:lifetime $($tail:tt)*) => {
92        $ts.extend([
93            ::proc_macro::TokenTree::from(
94                ::proc_macro::Punct::new('\'', ::proc_macro::Spacing::Joint)
95            ),
96            ::proc_macro::TokenTree::from(::proc_macro::Ident::new(
97                stringify!($l).trim_start_matches(|c| c == '\''),
98                ::proc_macro::Span::mixed_site(),
99            )),
100        ]);
101        quote_inner!($ts $($tail)*);
102    };
103
104    // Groups
105    ($ts:ident ($($inner:tt)*) $($tail:tt)*) => {
106        $ts.extend([::proc_macro::TokenTree::Group(::proc_macro::Group::new(
107            ::proc_macro::Delimiter::Parenthesis,
108            quote!($($inner)*)
109        ))]);
110        quote_inner!($ts $($tail)*);
111    };
112    ($ts:ident [$($inner:tt)*] $($tail:tt)*) => {
113        $ts.extend([::proc_macro::TokenTree::Group(::proc_macro::Group::new(
114            ::proc_macro::Delimiter::Bracket,
115            quote!($($inner)*)
116        ))]);
117        quote_inner!($ts $($tail)*);
118    };
119    ($ts:ident {$($inner:tt)*} $($tail:tt)*) => {
120        $ts.extend([::proc_macro::TokenTree::Group(::proc_macro::Group::new(
121            ::proc_macro::Delimiter::Brace,
122            quote!($($inner)*)
123        ))]);
124        quote_inner!($ts $($tail)*);
125    };
126
127    // Interpolated values
128    // TokenTree by default
129    ($ts:ident #($e:expr) $($tail:tt)*) => {
130        $ts.extend([$crate::to_tokens::ToTokenTree::into_token_tree($e)]);
131        quote_inner!($ts $($tail)*);
132    };
133    // Allow a TokenStream by request. It's more expensive, so avoid if possible.
134    ($ts:ident #S($e:expr) $($tail:tt)*) => {
135        $crate::to_tokens::ToTokenStream::append_to($e, $ts);
136        quote_inner!($ts $($tail)*);
137    };
138}