Review proc macro API 1.2 cc https://github.com/rust-lang/rust/issues/38356 Summary of applied changes: - Documentation for proc macro API 1.2 is expanded. - Renamed APIs: `Term` -> `Ident`, `TokenTree::Term` -> `TokenTree::Ident`, `Op` -> `Punct`, `TokenTree::Op` -> `TokenTree::Punct`, `Op::op` -> `Punct::as_char`. - Removed APIs: `Ident::as_str`, use `Display` impl for `Ident` instead. - New APIs (not stabilized in 1.2): `Ident::new_raw` for creating a raw identifier (I'm not sure `new_x` it's a very idiomatic name though). - Runtime changes: - `Punct::new` now ensures that the input `char` is a valid punctuation character in Rust. - `Ident::new` ensures that the input `str` is a valid identifier in Rust. - Lifetimes in proc macros are now represented as two joint tokens - `Punct('\'', Spacing::Joint)` and `Ident("lifetime_name_without_quote")` similarly to multi-character operators. - Stabilized APIs: None yet. A bit of motivation for renaming (although it was already stated in the review comments): - With my compiler frontend glasses on `Ident` is the single most appropriate name for this thing, *especially* if we are doing input validation on construction. `TokenTree::Ident` effectively wraps `token::Ident` or `ast::Ident + is_raw`, its meaning is "identifier" and it's already named `ident` in declarative macros. - Regarding `Punct`, the motivation is that `Op` is actively misleading. The thing doesn't mean an operator, it's neither a subset of operators (there is non-operator punctuation in the language), nor superset (operators can be multicharacter while this thing is always a single character). So I named it `Punct` (first proposed in [the original RFC](https://github.com/rust-lang/rfcs/pull/1566), then [by @SimonSapin](https://github.com/rust-lang/rust/issues/38356#issuecomment-276676526)) , together with input validation it's now a subset of ASCII punctuation character category (`u8::is_ascii_punctuation`). |
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| .. | ||
| diagnostics | ||
| ext | ||
| parse | ||
| util | ||
| ast.rs | ||
| attr.rs | ||
| build.rs | ||
| Cargo.toml | ||
| codemap.rs | ||
| config.rs | ||
| diagnostic_list.rs | ||
| edition.rs | ||
| entry.rs | ||
| feature_gate.rs | ||
| fold.rs | ||
| json.rs | ||
| lib.rs | ||
| ptr.rs | ||
| README.md | ||
| show_span.rs | ||
| std_inject.rs | ||
| str.rs | ||
| test.rs | ||
| test_snippet.rs | ||
| tokenstream.rs | ||
| visit.rs | ||
The syntax crate contains those things concerned purely with syntax
– that is, the AST ("abstract syntax tree"), parser, pretty-printer,
lexer, macro expander, and utilities for traversing ASTs.
For more information about how these things work in rustc, see the rustc guide: