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use crate::{Delimiter, Group, Ident, Literal, Punct, Spacing, Span, TokenStream, TokenTree};
macro_rules! quote_tt {
(($($t:tt)*)) => { Group::new(Delimiter::Parenthesis, quote!($($t)*)) };
([$($t:tt)*]) => { Group::new(Delimiter::Bracket, quote!($($t)*)) };
({$($t:tt)*}) => { Group::new(Delimiter::Brace, quote!($($t)*)) };
(,) => { Punct::new(',', Spacing::Alone) };
(.) => { Punct::new('.', Spacing::Alone) };
(;) => { Punct::new(';', Spacing::Alone) };
(!) => { Punct::new('!', Spacing::Alone) };
(<) => { Punct::new('<', Spacing::Alone) };
(>) => { Punct::new('>', Spacing::Alone) };
(&) => { Punct::new('&', Spacing::Alone) };
(=) => { Punct::new('=', Spacing::Alone) };
($i:ident) => { Ident::new(stringify!($i), Span::def_site()) };
}
macro_rules! quote_ts {
((@ $($t:tt)*)) => { $($t)* };
(::) => {
[
TokenTree::from(Punct::new(':', Spacing::Joint)),
TokenTree::from(Punct::new(':', Spacing::Alone)),
].iter()
.cloned()
.map(|mut x| {
x.set_span(Span::def_site());
x
})
.collect::<TokenStream>()
};
($t:tt) => { TokenTree::from(quote_tt!($t)) };
}
macro_rules! quote {
() => { TokenStream::new() };
($($t:tt)*) => {
[
$(TokenStream::from(quote_ts!($t)),)*
].iter().cloned().collect::<TokenStream>()
};
}
#[unstable(feature = "proc_macro_quote", issue = "54722")]
pub fn quote(stream: TokenStream) -> TokenStream {
if stream.is_empty() {
return quote!(crate::TokenStream::new());
}
let proc_macro_crate = quote!(crate);
let mut after_dollar = false;
let tokens = stream
.into_iter()
.filter_map(|tree| {
if after_dollar {
after_dollar = false;
match tree {
TokenTree::Ident(_) => {
return Some(quote!(Into::<crate::TokenStream>::into(
Clone::clone(&(@ tree))),));
}
TokenTree::Punct(ref tt) if tt.as_char() == '$' => {}
_ => panic!("`$` must be followed by an ident or `$` in `quote!`"),
}
} else if let TokenTree::Punct(ref tt) = tree {
if tt.as_char() == '$' {
after_dollar = true;
return None;
}
}
Some(quote!(crate::TokenStream::from((@ match tree {
TokenTree::Punct(tt) => quote!(crate::TokenTree::Punct(crate::Punct::new(
(@ TokenTree::from(Literal::character(tt.as_char()))),
(@ match tt.spacing() {
Spacing::Alone => quote!(crate::Spacing::Alone),
Spacing::Joint => quote!(crate::Spacing::Joint),
}),
))),
TokenTree::Group(tt) => quote!(crate::TokenTree::Group(crate::Group::new(
(@ match tt.delimiter() {
Delimiter::Parenthesis => quote!(crate::Delimiter::Parenthesis),
Delimiter::Brace => quote!(crate::Delimiter::Brace),
Delimiter::Bracket => quote!(crate::Delimiter::Bracket),
Delimiter::None => quote!(crate::Delimiter::None),
}),
(@ quote(tt.stream())),
))),
TokenTree::Ident(tt) => quote!(crate::TokenTree::Ident(crate::Ident::new(
(@ TokenTree::from(Literal::string(&tt.to_string()))),
(@ quote_span(proc_macro_crate.clone(), tt.span())),
))),
TokenTree::Literal(tt) => quote!(crate::TokenTree::Literal({
let mut iter = (@ TokenTree::from(Literal::string(&tt.to_string())))
.parse::<crate::TokenStream>()
.unwrap()
.into_iter();
if let (Some(crate::TokenTree::Literal(mut lit)), None) =
(iter.next(), iter.next())
{
lit.set_span((@ quote_span(proc_macro_crate.clone(), tt.span())));
lit
} else {
unreachable!()
}
}))
})),))
})
.collect::<TokenStream>();
if after_dollar {
panic!("unexpected trailing `$` in `quote!`");
}
quote!([(@ tokens)].iter().cloned().collect::<crate::TokenStream>())
}
#[unstable(feature = "proc_macro_quote", issue = "54722")]
pub fn quote_span(proc_macro_crate: TokenStream, span: Span) -> TokenStream {
let id = span.save_span();
quote!((@ proc_macro_crate ) ::Span::recover_proc_macro_span((@ TokenTree::from(Literal::usize_unsuffixed(id)))))
}