proc_macro_hack/
quote.rs

1use proc_macro::{Ident, TokenStream, TokenTree};
2use std::iter;
3
4macro_rules! quote {
5    () => {
6        ::proc_macro::TokenStream::new()
7    };
8    ($($tt:tt)*) => {{
9        let mut tokens = ::proc_macro::TokenStream::new();
10        quote_each_token!(tokens $($tt)*);
11        tokens
12    }};
13}
14
15macro_rules! quote_each_token {
16    ($tokens:ident # $var:ident $($rest:tt)*) => {
17        $crate::quote::Tokens::extend(&mut $tokens, &$var);
18        quote_each_token!($tokens $($rest)*);
19    };
20    ($tokens:ident $ident:ident $($rest:tt)*) => {
21        <::proc_macro::TokenStream as ::std::iter::Extend<_>>::extend(
22            &mut $tokens,
23            ::std::iter::once(
24                ::proc_macro::TokenTree::Ident(
25                    ::proc_macro::Ident::new(
26                        stringify!($ident),
27                        ::proc_macro::Span::call_site(),
28                    ),
29                ),
30            ),
31        );
32        quote_each_token!($tokens $($rest)*);
33    };
34    ($tokens:ident ( $($inner:tt)* ) $($rest:tt)*) => {
35        <::proc_macro::TokenStream as ::std::iter::Extend<_>>::extend(
36            &mut $tokens,
37            ::std::iter::once(
38                ::proc_macro::TokenTree::Group(
39                    ::proc_macro::Group::new(
40                        ::proc_macro::Delimiter::Parenthesis,
41                        quote!($($inner)*),
42                    ),
43                ),
44            ),
45        );
46        quote_each_token!($tokens $($rest)*);
47    };
48    ($tokens:ident [ $($inner:tt)* ] $($rest:tt)*) => {
49        <::proc_macro::TokenStream as ::std::iter::Extend<_>>::extend(
50            &mut $tokens,
51            ::std::iter::once(
52                ::proc_macro::TokenTree::Group(
53                    ::proc_macro::Group::new(
54                        ::proc_macro::Delimiter::Bracket,
55                        quote!($($inner)*),
56                    ),
57                ),
58            ),
59        );
60        quote_each_token!($tokens $($rest)*);
61    };
62    ($tokens:ident { $($inner:tt)* } $($rest:tt)*) => {
63        <::proc_macro::TokenStream as ::std::iter::Extend<_>>::extend(
64            &mut $tokens,
65            ::std::iter::once(
66                ::proc_macro::TokenTree::Group(
67                    ::proc_macro::Group::new(
68                        ::proc_macro::Delimiter::Brace,
69                        quote!($($inner)*),
70                    ),
71                ),
72            ),
73        );
74        quote_each_token!($tokens $($rest)*);
75    };
76    ($tokens:ident $punct:tt $($rest:tt)*) => {
77        <::proc_macro::TokenStream as ::std::iter::Extend<_>>::extend(
78            &mut $tokens,
79            stringify!($punct).parse::<::proc_macro::TokenStream>(),
80        );
81        quote_each_token!($tokens $($rest)*);
82    };
83    ($tokens:ident) => {};
84}
85
86pub trait Tokens {
87    fn extend(tokens: &mut TokenStream, var: &Self);
88}
89
90impl Tokens for Ident {
91    fn extend(tokens: &mut TokenStream, var: &Self) {
92        tokens.extend(iter::once(TokenTree::Ident(var.clone())));
93    }
94}
95
96impl Tokens for TokenStream {
97    fn extend(tokens: &mut TokenStream, var: &Self) {
98        tokens.extend(var.clone());
99    }
100}
101
102impl<T: Tokens> Tokens for Option<T> {
103    fn extend(tokens: &mut TokenStream, var: &Self) {
104        if let Some(var) = var {
105            T::extend(tokens, var);
106        }
107    }
108}
109
110impl<T: Tokens> Tokens for &T {
111    fn extend(tokens: &mut TokenStream, var: &Self) {
112        T::extend(tokens, var);
113    }
114}
proc_macro_hack/quote.rs

proc_macro_hack/
quote.rs
