Document the `proc_macro` feature in the Unstable Book
Discusses the `proc_macro` feature flag and the features it enables:
* Implicit enable of `extern_use_macros` feature and how to import proc macros
* Error handling in proc macros (using panic messages)
* Function-like proc macros using `#[proc_macro]` and a usage example for creating and invoking
* Attribute-like proc macros using `#[proc_macro_attribute]` and a usage example for creating and invoking
[Rendered](https://github.com/abonander/rust/blob/book_proc_macro/src/doc/unstable-book/src/language-features/proc-macro.md)
linkchecker: Add support for <base> tag
Add support for the HTML <base> tag as used by mdBook so The Unstable
Book can be checked.
Also cleanup a few things:
* Stop checking the name attribute. It should never have been used and
mdBook has since been fixed not to use it.
* Make sure we only check html files.
* Remove a few unnecessary allocations.
Finally, dead links in The Unstable Book have been fixed.
* Factor out the nigh-identical bodies of `_print` and `_eprint` to a helper
function `print_to` (I was sorely tempted to call it `_doprnt`).
* Update the issue number for the unstable `eprint` feature.
* Add entries to the "unstable book" for `eprint` and `eprint_internal`.
* Style corrections to the documentation.
1) changed "long way into" to "long way toward"
2) changed "developer lives" to "developers' lives"
3) removed the "either... or..." format from second paragraph because there are more than 2 options
4) Minor revisions to paragraphs 3-6 to make them more consistent in format and to fix minor grammar issues.
refactor NonZero, Shared, and Unique APIs
Major difference is that I removed Deref impls, as apparently LLVM has
trouble maintaining metadata with a `&ptr -> &ptr` API. This was cited
as a blocker for ever stabilizing this API. It wasn't that ergonomic
anyway.
* Added `get` to NonZero to replace Deref impl
* Added `ptr` getter to Shared/Unique to replace Deref impl
* Added Unique's `get` and `get_mut` conveniences to Shared
* Deprecated `as_mut_ptr` on Shared in favour of `ptr`
Note that Shared used to primarily expose only `*const` but there isn't
a good justification for that, so I made it `*mut`.
More methods for str boxes. (reduce Box<[u8]> ↔ Box<str> transmutes)
This is a follow-up to #41096 that adds safer methods for converting between `Box<str>` and `Box<[u8]>`. They're gated under a different feature from the `&mut str` methods because they may be too niche to include in public APIs, although having them internally helps reduce the number of transmutes the standard library uses.
What's added:
* `From<Box<str>> for Box<[u8]>`
* `<Box<str>>::into_boxed_bytes` (just calls `Into::into`)
* `alloc::str` (new module)
* `from_boxed_utf8` and `from_boxed_utf8_unchecked`, defined in `alloc:str`, exported in `collections::str`
* exports `from_utf8_mut` in `collections::str` (missed from previous PR)
Clarify the doc index
With regards to the unstable book, the reference, and the
processes involved.
Also, fix up a link by pointing to the new tracking issue rather than
the older one.
Fixes#41285
r? @frewsxcv
With regards to the unstable book, the reference, and the
processes involved.
Also, fix up a link by pointing to the new tracking issue rather than
the older one.
Fixes#41285
