Commit Graph

14 Commits

Author SHA1 Message Date
Vadim Petrochenkov
47d4089e10 TokenTree: Op -> Punct, Term -> Ident 2018-05-15 23:24:16 +03:00
John Kåre Alsaker
221b7ca3c2 Remove usages of Term::as_str and mark it for removal 2018-04-30 05:27:05 +02:00
Alex Crichton
79630d4fdf rustc: Tweak custom attribute capabilities
This commit starts to lay some groundwork for the stabilization of custom
attribute invocations and general procedural macros. It applies a number of
changes discussed on [internals] as well as a [recent issue][issue], namely:

* The path used to specify a custom attribute must be of length one and cannot
  be a global path. This'll help future-proof us against any ambiguities and
  give us more time to settle the precise syntax. In the meantime though a bare
  identifier can be used and imported to invoke a custom attribute macro. A new
  feature gate, `proc_macro_path_invoc`, was added to gate multi-segment paths
  and absolute paths.

* The set of items which can be annotated by a custom procedural attribute has
  been restricted. Statements, expressions, and modules are disallowed behind
  two new feature gates: `proc_macro_expr` and `proc_macro_mod`.

* The input to procedural macro attributes has been restricted and adjusted.
  Today an invocation like `#[foo(bar)]` will receive `(bar)` as the input token
  stream, but after this PR it will only receive `bar` (the delimiters were
  removed). Invocations like `#[foo]` are still allowed and will be invoked in
  the same way as `#[foo()]`. This is a **breaking change** for all nightly
  users as the syntax coming in to procedural macros will be tweaked slightly.

* Procedural macros (`foo!()` style) can only be expanded to item-like items by
  default. A separate feature gate, `proc_macro_non_items`, is required to
  expand to items like expressions, statements, etc.

Closes #50038

[internals]: https://internals.rust-lang.org/t/help-stabilize-a-subset-of-macros-2-0/7252
[issue]: https://github.com/rust-lang/rust/issues/50038
2018-04-20 19:56:16 -07:00
Alex Crichton
553c04d9eb 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/
2018-04-02 13:48:34 -07:00
Alex Crichton
d316874c87 Update and fix a few tests 2017-06-26 02:08:14 +00:00
Jeffrey Seyfried
71d4a860a1 Address review comments. 2017-06-26 02:06:34 +00:00
Jeffrey Seyfried
e42836b208 Implement quote! and other proc_macro API. 2017-06-26 02:06:26 +00:00
Jeffrey Seyfried
ce616a7d6a Improve the TokenStream quoter. 2017-03-15 23:05:02 +00:00
Jeffrey Seyfried
0d554139ad Fix fallout in unit tests. 2017-03-03 02:15:39 +00:00
Jeffrey Seyfried
2dc60b1180 Refactor TokenStream. 2017-01-22 21:37:38 +00:00
Jeffrey Seyfried
a8e86f0f81 Fix fallout in rustdoc and tests. 2016-11-21 12:16:46 +00:00
Nick Cameron
15821caee9 Split up libproc_macro_plugin
Separate the plugin code from non-plugin code to break a potential cycle in crates.

This will allow us to merge the new libproc_macro_tokens into libproc_macro.
2016-10-28 12:17:17 +13:00
Alex Crichton
2148bdfcc7 rustc: Rename rustc_macro to proc_macro
This commit blanket renames the `rustc_macro` infrastructure to `proc_macro`,
which reflects the general consensus of #35900. A follow up PR to Cargo will be
required to purge the `rustc-macro` name as well.
2016-10-06 11:07:23 -07:00
cgswords
98c8e0a05d Proc_macro is alive 2016-08-16 13:17:36 -07:00