332dffb1f9
A `TokenStream` contains a `Lrc<Vec<(TokenTree, Spacing)>>`. But this is
not quite right. `Spacing` makes sense for `TokenTree::Token`, but does
not make sense for `TokenTree::Delimited`, because a
`TokenTree::Delimited` cannot be joined with another `TokenTree`.
This commit fixes this problem, by adding `Spacing` to `TokenTree::Token`,
changing `TokenStream` to contain a `Lrc<Vec<TokenTree>>`, and removing the
`TreeAndSpacing` typedef.
The commit removes these two impls:
- `impl From<TokenTree> for TokenStream`
- `impl From<TokenTree> for TreeAndSpacing`
These were useful, but also resulted in code with many `.into()` calls
that was hard to read, particularly for anyone not highly familiar with
the relevant types. This commit makes some other changes to compensate:
- `TokenTree::token()` becomes `TokenTree::token_{alone,joint}()`.
- `TokenStream::token_{alone,joint}()` are added.
- `TokenStream::delimited` is added.
This results in things like this:
```rust
TokenTree::token(token::Semi, stmt.span).into()
```
changing to this:
```rust
TokenStream::token_alone(token::Semi, stmt.span)
```
This makes the type of the result, and its spacing, clearer.
These changes also simplifies `Cursor` and `CursorRef`, because they no longer
need to distinguish between `next` and `next_with_spacing`.
71 lines
2.1 KiB
Rust
71 lines
2.1 KiB
Rust
use rustc_ast as ast;
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use rustc_ast::ptr::P;
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use rustc_ast::token::{self, Token};
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use rustc_ast::tokenstream::{TokenStream, TokenTree};
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use rustc_expand::base::{self, *};
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use rustc_span::symbol::{Ident, Symbol};
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use rustc_span::Span;
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pub fn expand_concat_idents<'cx>(
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cx: &'cx mut ExtCtxt<'_>,
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sp: Span,
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tts: TokenStream,
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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.into_trees().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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if let TokenTree::Token(token, _) = e {
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if let Some((ident, _)) = token.ident() {
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res_str.push_str(ident.name.as_str());
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continue;
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}
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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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let ident = Ident::new(Symbol::intern(&res_str), cx.with_call_site_ctxt(sp));
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struct ConcatIdentsResult {
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ident: Ident,
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}
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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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kind: ast::ExprKind::Path(None, ast::Path::from_ident(self.ident)),
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span: self.ident.span,
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attrs: ast::AttrVec::new(),
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tokens: None,
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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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kind: ast::TyKind::Path(None, ast::Path::from_ident(self.ident)),
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span: self.ident.span,
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tokens: None,
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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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