65 lines
2.2 KiB
Rust
65 lines
2.2 KiB
Rust
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//! Each macro must have a definition, so `#[plugin]` attributes
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//! inject a dummy `macro_rules` item for each macro they define.
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use syntax::ast::*;
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use syntax::attr;
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use syntax::edition::Edition;
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use syntax::ext::base::{Resolver, NamedSyntaxExtension};
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use syntax::parse::token;
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use syntax::ptr::P;
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use syntax::source_map::respan;
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use syntax::symbol::sym;
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use syntax::tokenstream::*;
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use syntax_pos::{Span, DUMMY_SP};
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use syntax_pos::hygiene::{ExpnId, ExpnInfo, ExpnKind, MacroKind};
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use std::mem;
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fn plugin_macro_def(name: Name, span: Span) -> P<Item> {
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let rustc_builtin_macro = Attribute {
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id: attr::mk_attr_id(),
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style: AttrStyle::Outer,
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path: Path::from_ident(Ident::new(sym::rustc_builtin_macro, span)),
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tokens: TokenStream::empty(),
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is_sugared_doc: false,
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span,
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};
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let parens: TreeAndJoint = TokenTree::Delimited(
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DelimSpan::from_single(span), token::Paren, TokenStream::empty()
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).into();
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let trees = vec![parens.clone(), TokenTree::token(token::FatArrow, span).into(), parens];
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P(Item {
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ident: Ident::new(name, span),
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attrs: vec![rustc_builtin_macro],
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id: DUMMY_NODE_ID,
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node: ItemKind::MacroDef(MacroDef { tokens: TokenStream::new(trees), legacy: true }),
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vis: respan(span, VisibilityKind::Inherited),
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span: span,
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tokens: None,
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})
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}
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pub fn inject(
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krate: &mut Crate,
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resolver: &mut dyn Resolver,
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named_exts: Vec<NamedSyntaxExtension>,
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edition: Edition,
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) {
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if !named_exts.is_empty() {
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let mut extra_items = Vec::new();
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let span = DUMMY_SP.fresh_expansion(ExpnId::root(), ExpnInfo::allow_unstable(
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ExpnKind::Macro(MacroKind::Attr, sym::plugin), DUMMY_SP, edition,
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[sym::rustc_attrs][..].into(),
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));
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for (name, ext) in named_exts {
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resolver.register_builtin_macro(Ident::with_empty_ctxt(name), ext);
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extra_items.push(plugin_macro_def(name, span));
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}
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// The `macro_rules` items must be inserted before any other items.
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mem::swap(&mut extra_items, &mut krate.module.items);
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krate.module.items.append(&mut extra_items);
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}
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}
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