e6947ecf4d
proc_macro: Reorganize public API This commit is a reorganization of the `proc_macro` crate's public user-facing API. This is the result of a number of discussions at the recent Rust All-Hands where we're hoping to get the `proc_macro` crate into ship shape for stabilization of a subset of its functionality in the Rust 2018 release. The reorganization here is motivated by experiences from the `proc-macro2`, `quote`, and `syn` crates on crates.io (and other crates which depend on them). The main focus is future flexibility along with making a few more operations consistent and/or fixing bugs. A summary of the changes made from today's `proc_macro` API is: * The `TokenNode` enum has been removed and the public fields of `TokenTree` have also been removed. Instead the `TokenTree` type is now a public enum (what `TokenNode` was) and each variant is an opaque struct which internally contains `Span` information. This makes the various tokens a bit more consistent, require fewer wrappers, and otherwise provides good future-compatibility as opaque structs are easy to modify later on. * `Literal` integer constructors have been expanded to be unambiguous as to what they're doing and also allow for more future flexibility. Previously constructors like `Literal::float` and `Literal::integer` were used to create unsuffixed literals and the concrete methods like `Literal::i32` would create a suffixed token. This wasn't immediately clear to all users (the suffixed/unsuffixed aspect) and having *one* constructor for unsuffixed literals required us to pick a largest type which may not always be true. To fix these issues all constructors are now of the form `Literal::i32_unsuffixed` or `Literal::i32_suffixed` (for all integral types). This should allow future compatibility as well as being immediately clear what's suffixed and what isn't. * Each variant of `TokenTree` internally contains a `Span` which can also be configured via `set_span`. For example `Literal` and `Term` now both internally contain a `Span` rather than having it stored in an auxiliary location. * Constructors of all tokens are called `new` now (aka `Term::intern` is gone) and most do not take spans. Manufactured tokens typically don't have a fresh span to go with them and the span is purely used for error-reporting **except** the span for `Term`, which currently affects hygiene. The default spans for all these constructed tokens is `Span::call_site()` for now. The `Term` type's constructor explicitly requires passing in a `Span` to provide future-proofing against possible hygiene changes. It's intended that a first pass of stabilization will likely only stabilize `Span::call_site()` which is an explicit opt-in for "I would like no hygiene here please". The intention here is to make this explicit in procedural macros to be forwards-compatible with a hygiene-specifying solution. * Some of the conversions for `TokenStream` have been simplified a little. * The `TokenTreeIter` iterator was renamed to `token_stream::IntoIter`. Overall the hope is that this is the "final pass" at the API of `TokenStream` and most of `TokenTree` before stabilization. Explicitly left out here is any changes to `Span`'s API which will likely need to be re-evaluated before stabilization. All changes in this PR have already been reflected to the [`proc-macro2`], `quote`, and `syn` crates. New versions of all these crates have also been published to crates.io. Once this lands in nightly I plan on making an internals post again summarizing the changes made here and also calling on all macro authors to give the APIs a spin and see how they work. Hopefully pending no major issues we can then have an FCP to stabilize later this cycle! [`proc-macro2`]: https://docs.rs/proc-macro2/0.3.1/proc_macro2/ Closes #49596 |
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| .. | ||
| auxiliary | ||
| proc-macro | ||
| ast_stmt_expr_attr.rs | ||
| compiler-calls.rs | ||
| create-dir-all-bare.rs | ||
| custom-derive-partial-eq.rs | ||
| derive-no-std-not-supported.rs | ||
| derive-totalsum-attr.rs | ||
| derive-totalsum.rs | ||
| deriving-encodable-decodable-box.rs | ||
| deriving-encodable-decodable-cell-refcell.rs | ||
| deriving-global.rs | ||
| dropck_tarena_sound_drop.rs | ||
| empty-struct-braces-derive.rs | ||
| extern-mod-syntax.rs | ||
| issue_24106.rs | ||
| issue-2804.rs | ||
| issue-4016.rs | ||
| issue-4036.rs | ||
| issue-11881.rs | ||
| issue-13560.rs | ||
| issue-14021.rs | ||
| issue-15149.rs | ||
| issue-15778-pass.rs | ||
| issue-15924.rs | ||
| issue-16723.rs | ||
| issue-16822.rs | ||
| issue-16992.rs | ||
| issue-18502.rs | ||
| issue-18763-quote-token-tree.rs | ||
| issue-24972.rs | ||
| issue-35829.rs | ||
| issue-40663.rs | ||
| linkage-visibility.rs | ||
| llvm-pass-plugin.rs | ||
| lto-syntax-extension.rs | ||
| macro-crate-does-hygiene-work.rs | ||
| macro-crate-multi-decorator-literals.rs | ||
| macro-crate-multi-decorator.rs | ||
| macro-crate.rs | ||
| macro-quote-cond.rs | ||
| macro-quote-test.rs | ||
| mbe_matching_test_macro.rs | ||
| myriad-closures.rs | ||
| outlive-expansion-phase.rs | ||
| plugin-args-1.rs | ||
| plugin-args-2.rs | ||
| plugin-args-3.rs | ||
| plugin-lib-ok-in-plugin.rs | ||
| plugin-plus-extern-crate.rs | ||
| pprust-expr-roundtrip.rs | ||
| proc_macro.rs | ||
| qquote.rs | ||
| quote-tokens.rs | ||
| quote-unused-sp-no-warning.rs | ||
| regions-mock-tcx.rs | ||
| rename-directory.rs | ||
| roman-numerals-macro.rs | ||
| rustc_encodable_hygiene.rs | ||
| stdio-from.rs | ||
| switch-stdout.rs | ||
| syntax-extension-with-dll-deps.rs | ||