67 lines
2.1 KiB
Rust
67 lines
2.1 KiB
Rust
use rustc_data_structures::thin_vec::ThinVec;
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use syntax::ast;
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use syntax::ext::base::{self, *};
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use syntax::parse::token::{self, Token};
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use syntax::ptr::P;
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use syntax_pos::Span;
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use syntax_pos::symbol::Symbol;
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use syntax::tokenstream::TokenTree;
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pub fn expand_syntax_ext<'cx>(cx: &'cx mut ExtCtxt<'_>,
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sp: Span,
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tts: &[TokenTree])
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-> Box<dyn base::MacResult + 'cx> {
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if tts.is_empty() {
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cx.span_err(sp, "concat_idents! takes 1 or more arguments.");
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return DummyResult::any(sp);
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}
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let mut res_str = String::new();
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for (i, e) in tts.iter().enumerate() {
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if i & 1 == 1 {
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match *e {
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TokenTree::Token(Token { kind: token::Comma, .. }) => {}
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_ => {
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cx.span_err(sp, "concat_idents! expecting comma.");
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return DummyResult::any(sp);
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}
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}
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} else {
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match *e {
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TokenTree::Token(Token { kind: token::Ident(name, _), .. }) =>
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res_str.push_str(&name.as_str()),
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_ => {
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cx.span_err(sp, "concat_idents! requires ident args.");
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return DummyResult::any(sp);
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}
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}
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}
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}
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let ident = ast::Ident::new(Symbol::intern(&res_str), sp.apply_mark(cx.current_expansion.id));
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struct ConcatIdentsResult { ident: ast::Ident }
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impl base::MacResult for ConcatIdentsResult {
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fn make_expr(self: Box<Self>) -> Option<P<ast::Expr>> {
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Some(P(ast::Expr {
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id: ast::DUMMY_NODE_ID,
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node: ast::ExprKind::Path(None, ast::Path::from_ident(self.ident)),
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span: self.ident.span,
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attrs: ThinVec::new(),
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}))
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}
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fn make_ty(self: Box<Self>) -> Option<P<ast::Ty>> {
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Some(P(ast::Ty {
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id: ast::DUMMY_NODE_ID,
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node: ast::TyKind::Path(None, ast::Path::from_ident(self.ident)),
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span: self.ident.span,
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}))
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}
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}
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Box::new(ConcatIdentsResult { ident })
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}
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