proc_macro: clean up the implementation of quasi-quoting.
This commit is contained in:
Eduard-Mihai Burtescu
parent
d10d0b3e9e
commit
56aaa53278
4 changed files with 99 additions and 183 deletions
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@ -145,6 +145,9 @@ impl fmt::Debug for TokenStream {
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}
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}
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#[unstable(feature = "proc_macro_quote", issue = "38356")]
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pub use quote::{quote, quote_span};
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/// Creates a token stream containing a single token tree.
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#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
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impl From<TokenTree> for TokenStream {
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@ -237,7 +240,7 @@ pub mod token_stream {
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/// Unquoting is done with `$`, and works by taking the single next ident as the unquoted term.
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/// To quote `$` itself, use `$$`.
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///
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/// This is a dummy macro, the actual implementation is in quote::Quoter
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/// This is a dummy macro, the actual implementation is in `quote::quote`.`
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#[unstable(feature = "proc_macro_quote", issue = "38356")]
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#[macro_export]
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macro_rules! quote { () => {} }
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@ -246,13 +249,6 @@ macro_rules! quote { () => {} }
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#[doc(hidden)]
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mod quote;
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/// Quote a `Span` into a `TokenStream`.
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/// This is needed to implement a custom quoter.
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#[unstable(feature = "proc_macro_quote", issue = "38356")]
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pub fn quote_span(span: Span) -> TokenStream {
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quote::Quote::quote(span)
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}
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/// A region of source code, along with macro expansion information.
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#[stable(feature = "proc_macro_lib2", since = "1.29.0")]
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#[derive(Copy, Clone)]
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@ -1364,8 +1360,6 @@ impl TokenTree {
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#[unstable(feature = "proc_macro_internals", issue = "27812")]
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#[doc(hidden)]
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pub mod __internal {
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pub use quote::{Quoter, unquote};
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use std::cell::Cell;
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use std::ptr;
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@ -14,34 +14,26 @@
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//! This quasiquoter uses macros 2.0 hygiene to reliably access
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//! items from `proc_macro`, to build a `proc_macro::TokenStream`.
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use {Delimiter, Literal, Spacing, Span, Ident, Punct, Group, TokenStream, TokenTree};
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use {Delimiter, Group, Ident, Literal, Punct, Spacing, Span, TokenStream, TokenTree};
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use syntax::ext::base::{ExtCtxt, ProcMacro};
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use syntax::tokenstream;
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/// This is the actual quote!() proc macro
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///
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/// It is manually loaded in CStore::load_macro_untracked
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pub struct Quoter;
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pub fn unquote<T: Into<TokenStream> + Clone>(tokens: &T) -> TokenStream {
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tokens.clone().into()
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macro_rules! quote_tt {
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(($($t:tt)*)) => { Group::new(Delimiter::Parenthesis, quote!($($t)*)) };
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([$($t:tt)*]) => { Group::new(Delimiter::Bracket, quote!($($t)*)) };
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({$($t:tt)*}) => { Group::new(Delimiter::Brace, quote!($($t)*)) };
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(,) => { Punct::new(',', Spacing::Alone) };
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(.) => { Punct::new('.', Spacing::Alone) };
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(:) => { Punct::new(':', Spacing::Alone) };
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(;) => { Punct::new(';', Spacing::Alone) };
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(!) => { Punct::new('!', Spacing::Alone) };
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(<) => { Punct::new('<', Spacing::Alone) };
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(>) => { Punct::new('>', Spacing::Alone) };
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(&) => { Punct::new('&', Spacing::Alone) };
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(=) => { Punct::new('=', Spacing::Alone) };
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($i:ident) => { Ident::new(stringify!($i), Span::def_site()) };
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}
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pub trait Quote {
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fn quote(self) -> TokenStream;
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}
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macro_rules! tt2ts {
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($e:expr) => (TokenStream::from(TokenTree::from($e)))
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}
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macro_rules! quote_tok {
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(,) => { tt2ts!(Punct::new(',', Spacing::Alone)) };
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(.) => { tt2ts!(Punct::new('.', Spacing::Alone)) };
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(:) => { tt2ts!(Punct::new(':', Spacing::Alone)) };
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(;) => { tt2ts!(Punct::new(';', Spacing::Alone)) };
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(|) => { tt2ts!(Punct::new('|', Spacing::Alone)) };
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macro_rules! quote_ts {
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((@ $($t:tt)*)) => { $($t)* };
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(::) => {
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[
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TokenTree::from(Punct::new(':', Spacing::Joint)),
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@ -54,57 +46,45 @@ macro_rules! quote_tok {
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})
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.collect::<TokenStream>()
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};
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(!) => { tt2ts!(Punct::new('!', Spacing::Alone)) };
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(<) => { tt2ts!(Punct::new('<', Spacing::Alone)) };
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(>) => { tt2ts!(Punct::new('>', Spacing::Alone)) };
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(_) => { tt2ts!(Punct::new('_', Spacing::Alone)) };
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(0) => { tt2ts!(Literal::i8_unsuffixed(0)) };
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(&) => { tt2ts!(Punct::new('&', Spacing::Alone)) };
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(=) => { tt2ts!(Punct::new('=', Spacing::Alone)) };
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($i:ident) => { tt2ts!(Ident::new(stringify!($i), Span::def_site())) };
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}
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macro_rules! quote_tree {
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((unquote $($t:tt)*)) => { $($t)* };
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((quote $($t:tt)*)) => { ($($t)*).quote() };
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(($($t:tt)*)) => { tt2ts!(Group::new(Delimiter::Parenthesis, quote!($($t)*))) };
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([$($t:tt)*]) => { tt2ts!(Group::new(Delimiter::Bracket, quote!($($t)*))) };
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({$($t:tt)*}) => { tt2ts!(Group::new(Delimiter::Brace, quote!($($t)*))) };
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($t:tt) => { quote_tok!($t) };
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($t:tt) => { TokenTree::from(quote_tt!($t)) };
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}
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/// Simpler version of the real `quote!` macro, implemented solely
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/// through `macro_rules`, for bootstrapping the real implementation
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/// (see the `quote` function), which does not have access to the
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/// real `quote!` macro due to the `proc_macro` crate not being
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/// able to depend on itself.
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///
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/// Note: supported tokens are a subset of the real `quote!`, but
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/// unquoting is different: instead of `$x`, this uses `(@ expr)`.
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macro_rules! quote {
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() => { TokenStream::new() };
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($($t:tt)*) => {
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[$(quote_tree!($t),)*].iter()
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.cloned()
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.flat_map(|x| x.into_iter())
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.collect::<TokenStream>()
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[
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$(TokenStream::from(quote_ts!($t)),)*
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].iter().cloned().collect::<TokenStream>()
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};
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}
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impl ProcMacro for Quoter {
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fn expand<'cx>(&self, cx: &'cx mut ExtCtxt,
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_: ::syntax_pos::Span,
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stream: tokenstream::TokenStream)
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-> tokenstream::TokenStream {
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::__internal::set_sess(cx, || TokenStream(stream).quote().0)
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/// Quote a `TokenStream` into a `TokenStream`.
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/// This is the actual `quote!()` proc macro.
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///
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/// It is manually loaded in `CStore::load_macro_untracked`.
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#[unstable(feature = "proc_macro_quote", issue = "38356")]
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pub fn quote(stream: TokenStream) -> TokenStream {
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if stream.is_empty() {
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return quote!(::TokenStream::new());
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}
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}
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impl Quote for TokenStream {
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fn quote(self) -> TokenStream {
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if self.is_empty() {
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return quote!(::TokenStream::new());
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}
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let mut after_dollar = false;
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let tokens = self.into_iter().filter_map(|tree| {
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let mut after_dollar = false;
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let tokens = stream
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.into_iter()
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.filter_map(|tree| {
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if after_dollar {
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after_dollar = false;
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match tree {
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TokenTree::Ident(_) => {
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let tree = TokenStream::from(tree);
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return Some(quote!(::__internal::unquote(&(unquote tree)),));
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return Some(quote!(Into::<::TokenStream>::into(
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Clone::clone(&(@ tree))),));
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}
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TokenTree::Punct(ref tt) if tt.as_char() == '$' => {}
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_ => panic!("`$` must be followed by an ident or `$` in `quote!`"),
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@ -116,116 +96,55 @@ impl Quote for TokenStream {
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}
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}
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Some(quote!(::TokenStream::from((quote tree)),))
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}).flat_map(|t| t.into_iter()).collect::<TokenStream>();
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Some(quote!(::TokenStream::from((@ match tree {
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TokenTree::Punct(tt) => quote!(::TokenTree::Punct(::Punct::new(
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(@ TokenTree::from(Literal::character(tt.as_char()))),
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(@ match tt.spacing() {
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Spacing::Alone => quote!(::Spacing::Alone),
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Spacing::Joint => quote!(::Spacing::Joint),
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}),
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))),
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TokenTree::Group(tt) => quote!(::TokenTree::Group(::Group::new(
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(@ match tt.delimiter() {
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Delimiter::Parenthesis => quote!(::Delimiter::Parenthesis),
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Delimiter::Brace => quote!(::Delimiter::Brace),
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Delimiter::Bracket => quote!(::Delimiter::Bracket),
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Delimiter::None => quote!(::Delimiter::None),
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}),
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(@ quote(tt.stream())),
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))),
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TokenTree::Ident(tt) => quote!(::TokenTree::Ident(::Ident::new(
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(@ TokenTree::from(Literal::string(&tt.to_string()))),
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(@ quote_span(tt.span())),
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))),
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TokenTree::Literal(tt) => quote!(::TokenTree::Literal({
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let mut iter = (@ TokenTree::from(Literal::string(&tt.to_string())))
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.parse::<::TokenStream>()
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.unwrap()
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.into_iter();
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if let (Some(::TokenTree::Literal(mut lit)), None) =
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(iter.next(), iter.next())
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{
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lit.set_span((@ quote_span(tt.span())));
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lit
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} else {
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unreachable!()
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}
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}))
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})),))
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})
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.collect::<TokenStream>();
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if after_dollar {
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panic!("unexpected trailing `$` in `quote!`");
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}
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quote!(
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[(unquote tokens)].iter()
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.cloned()
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.flat_map(|x| x.into_iter())
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.collect::<::TokenStream>()
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)
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if after_dollar {
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panic!("unexpected trailing `$` in `quote!`");
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}
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quote!([(@ tokens)].iter().cloned().collect::<::TokenStream>())
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}
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impl Quote for TokenTree {
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fn quote(self) -> TokenStream {
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match self {
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TokenTree::Punct(tt) => quote!(::TokenTree::Punct( (quote tt) )),
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TokenTree::Group(tt) => quote!(::TokenTree::Group( (quote tt) )),
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TokenTree::Ident(tt) => quote!(::TokenTree::Ident( (quote tt) )),
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TokenTree::Literal(tt) => quote!(::TokenTree::Literal( (quote tt) )),
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}
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}
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}
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impl Quote for char {
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fn quote(self) -> TokenStream {
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TokenTree::from(Literal::character(self)).into()
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}
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}
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impl<'a> Quote for &'a str {
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fn quote(self) -> TokenStream {
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TokenTree::from(Literal::string(self)).into()
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}
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}
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impl Quote for u16 {
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fn quote(self) -> TokenStream {
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TokenTree::from(Literal::u16_unsuffixed(self)).into()
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}
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}
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impl Quote for Group {
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fn quote(self) -> TokenStream {
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quote!(::Group::new((quote self.delimiter()), (quote self.stream())))
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}
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}
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impl Quote for Punct {
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fn quote(self) -> TokenStream {
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quote!(::Punct::new((quote self.as_char()), (quote self.spacing())))
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}
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}
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impl Quote for Ident {
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fn quote(self) -> TokenStream {
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quote!(::Ident::new((quote self.sym.as_str()), (quote self.span())))
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}
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}
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impl Quote for Span {
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fn quote(self) -> TokenStream {
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quote!(::Span::def_site())
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}
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}
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impl Quote for Literal {
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fn quote(self) -> TokenStream {
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quote! {{
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let mut iter = (quote self.to_string())
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.parse::<::TokenStream>()
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.unwrap()
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.into_iter();
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if let (Some(::TokenTree::Literal(mut lit)), None) = (iter.next(), iter.next()) {
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lit.set_span((quote self.span));
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lit
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} else {
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unreachable!()
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}
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}}
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}
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}
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impl Quote for Delimiter {
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fn quote(self) -> TokenStream {
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macro_rules! gen_match {
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($($i:ident),*) => {
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match self {
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$(Delimiter::$i => { quote!(::Delimiter::$i) })*
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}
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}
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}
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gen_match!(Parenthesis, Brace, Bracket, None)
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}
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}
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impl Quote for Spacing {
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fn quote(self) -> TokenStream {
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macro_rules! gen_match {
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($($i:ident),*) => {
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match self {
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$(Spacing::$i => { quote!(::Spacing::$i) })*
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}
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}
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}
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gen_match!(Alone, Joint)
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}
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/// Quote a `Span` into a `TokenStream`.
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/// This is needed to implement a custom quoter.
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#[unstable(feature = "proc_macro_quote", issue = "38356")]
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pub fn quote_span(_: Span) -> TokenStream {
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quote!(::Span::def_site())
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}
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@ -39,7 +39,6 @@ use syntax::ast;
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use syntax::attr;
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use syntax::codemap;
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use syntax::edition::Edition;
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use syntax::ext::base::SyntaxExtension;
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use syntax::parse::filemap_to_stream;
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use syntax::symbol::Symbol;
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use syntax_pos::{Span, NO_EXPANSION, FileName};
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@ -517,8 +516,11 @@ impl CrateStore for cstore::CStore {
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return LoadedMacro::ProcMacro(proc_macros[id.index.to_proc_macro_index()].1.clone());
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} else if data.name == "proc_macro" &&
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self.get_crate_data(id.krate).item_name(id.index) == "quote" {
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use syntax::ext::base::SyntaxExtension;
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use syntax_ext::proc_macro_impl::BangProcMacro;
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let ext = SyntaxExtension::ProcMacro {
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expander: Box::new(::proc_macro::__internal::Quoter),
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expander: Box::new(BangProcMacro { inner: ::proc_macro::quote }),
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allow_internal_unstable: true,
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edition: data.root.edition,
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};
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@ -19,6 +19,7 @@
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#![feature(libc)]
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#![feature(macro_at_most_once_rep)]
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#![feature(proc_macro_internals)]
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#![feature(proc_macro_quote)]
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#![feature(quote)]
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#![feature(rustc_diagnostic_macros)]
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#![feature(slice_sort_by_cached_key)]
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