bjoernager/rust
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Declarative macros 2.0 without hygiene.

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This commit is contained in:
Jeffrey Seyfried 2017-03-18 01:55:51 +00:00
parent 9c6430b325
commit 2a1d2edb82
14 changed files with 116 additions and 46 deletions
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68
src/libsyntax/parse/parser.rs
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@ -3758,33 +3758,59 @@ impl<'a> Parser<'a> {
fn eat_macro_def(&mut self, attrs: &[Attribute], vis: &Visibility)
-> PResult<'a, Option<P<Item>>> {
let lo = self.span;
match self.token {
token::Ident(ident) if ident.name == "macro_rules" => {
if self.look_ahead(1, |t| *t == token::Not) {
let prev_span = self.prev_span;
self.complain_if_pub_macro(vis, prev_span);
self.bump();
self.bump();
let (ident, def) = match self.token {
token::Ident(ident) if ident.name == keywords::Macro.name() => {
self.bump();
let ident = self.parse_ident()?;
let tokens = if self.check(&token::OpenDelim(token::Brace)) {
match self.parse_token_tree() {
TokenTree::Delimited(_, ref delimited) => delimited.stream(),
_ => unreachable!(),
}
} else if self.check(&token::OpenDelim(token::Paren)) {
let args = self.parse_token_tree();
let body = if self.check(&token::OpenDelim(token::Brace)) {
self.parse_token_tree()
} else {
self.unexpected()?;
unreachable!()
};
TokenStream::concat(vec![
args.into(),
TokenTree::Token(lo.to(self.prev_span), token::FatArrow).into(),
body.into(),
])
} else {
self.unexpected()?;
unreachable!()
};
(ident, ast::MacroDef { tokens: tokens.into(), legacy: false })
}
token::Ident(ident) if ident.name == "macro_rules" &&
self.look_ahead(1, |t| *t == token::Not) => {
let prev_span = self.prev_span;
self.complain_if_pub_macro(vis, prev_span);
self.bump();
self.bump();
let ident = self.parse_ident()?;
let (delim, tokens) = self.expect_delimited_token_tree()?;
if delim != token::Brace {
if !self.eat(&token::Semi) {
let msg = "macros that expand to items must either \
be surrounded with braces or followed by a semicolon";
self.span_err(self.prev_span, msg);
}
}
(ident, ast::MacroDef { tokens: tokens, legacy: true })
}
_ => return Ok(None),
};
let id = self.parse_ident()?;
let (delim, tts) = self.expect_delimited_token_tree()?;
if delim != token::Brace {
if !self.eat(&token::Semi) {
let msg = "macros that expand to items must either be surrounded with braces \
or followed by a semicolon";
self.span_err(self.prev_span, msg);
}
}
let span = lo.to(self.prev_span);
let kind = ItemKind::MacroDef(ast::MacroDef {
tokens: tts,
});
Ok(Some(self.mk_item(span, id, kind, Visibility::Inherited, attrs.to_owned())))
Ok(Some(self.mk_item(span, ident, ItemKind::MacroDef(def), vis.clone(), attrs.to_vec())))
}
fn parse_stmt_without_recovery(&mut self,