Clarify documentation for string slicing (Index impls)
Clarify documentation for string slicing (Index impls)
- Mention the sugared syntax for the implementations, since it's not
apparent from the docs that `Index<Range<usize>>` corresponds to
`&self[a..b]`.
- Be specific in that start <= end and end <= len
This is just one fix in response to #32057
- Mention the sugared syntax for the implementations, since it's not
apparent from the docs that `Index<Range<usize>>` corresponds to
`&self[a..b]`.
- Be specific in that start <= end and end <= len
Fix panic on string slicing error to truncate the string
The string may be arbitrarily long, but we want to limit the panic
message to a reasonable length. Truncate the string if it is too long
(simply to char boundary).
Also add details to the start <= end message. I think it's ok to flesh
out the code here, since it's in a cold function.
Fixes#32063
This PR implements [RFC 1192](https://github.com/rust-lang/rfcs/blob/master/text/1192-inclusive-ranges.md), which is triple-dot syntax for inclusive range expressions. The new stuff is behind two feature gates (one for the syntax and one for the std::ops types). This replaces the deprecated functionality in std::iter. Along the way I simplified the desugaring for all ranges.
This is my first contribution to rust which changes more than one character outside of a test or comment, so please review carefully! Some of the individual commit messages have more of my notes. Also thanks for putting up with my dumb questions in #rust-internals.
- For implementing `std::ops::RangeInclusive`, I took @Stebalien's suggestion from https://github.com/rust-lang/rfcs/pull/1192#issuecomment-137864421. It seemed to me to make the implementation easier and increase type safety. If that stands, the RFC should be amended to avoid confusion.
- I also kind of like @glaebhoerl's [idea](https://github.com/rust-lang/rfcs/pull/1254#issuecomment-147815299), which is unified inclusive/exclusive range syntax something like `x>..=y`. We can experiment with this while everything is behind a feature gate.
- There are a couple of FIXMEs left (see the last commit). I didn't know what to do about `RangeArgument` and I haven't added `Index` impls yet. Those should be discussed/finished before merging.
cc @Gankro since you [complained](https://www.reddit.com/r/rust/comments/3xkfro/what_happened_to_inclusive_ranges/cy5j0yq)
cc #27777#30877rust-lang/rust#1192rust-lang/rfcs#1254
relevant to #28237 (tracking issue)
The string may be arbitrarily long, but we want to limit the panic
message to a reasonable length. Truncate the string if it is too long
(simply to char boundary).
Also add details to the start <= end message. I think it's ok to flesh
out the code here, since it's in a cold function.
Use raw pointer casts for slice, str's .as_ptr()
We can now use raw pointer casts `*const [T] as *const T` and
`*const str as *const u8` instead of .repr() for getting the
pointer out of a slice.
These types were already `!Sync`, but this improves error messages when they are used in contexts that require `Sync`, aligning them with conventions used with `Rc`, among others.
r? @alexcrichton
These types were already `!Sync`, but this improves error messages when
they are used in contexts that require `Sync`, aligning them with
conventions used with `Rc`, among others.
Hello.
Quite a few of the links in the `core` module concerning redirection to additional primitive type documentation are broken. I noticed in #30214 that there seemed to be a consensus with linking across to `std` module documentation from the `core` module. This is what I've done with the `core` modules for primitive types.
If the changes here are good to go forward with, I'll happily tend to adding more documentation links for the extension traits in the aforementioned issue if need be.
r? @steveklabnik
This commit is the result of the FCPs ending for the 1.8 release cycle for both
the libs and the lang suteams. The full list of changes are:
Stabilized
* `braced_empty_structs`
* `augmented_assignments`
* `str::encode_utf16` - renamed from `utf16_units`
* `str::EncodeUtf16` - renamed from `Utf16Units`
* `Ref::map`
* `RefMut::map`
* `ptr::drop_in_place`
* `time::Instant`
* `time::SystemTime`
* `{Instant,SystemTime}::now`
* `{Instant,SystemTime}::duration_since` - renamed from `duration_from_earlier`
* `{Instant,SystemTime}::elapsed`
* Various `Add`/`Sub` impls for `Time` and `SystemTime`
* `SystemTimeError`
* `SystemTimeError::duration`
* Various impls for `SystemTimeError`
* `UNIX_EPOCH`
* `ops::{Add,Sub,Mul,Div,Rem,BitAnd,BitOr,BitXor,Shl,Shr}Assign`
Deprecated
* Scoped TLS (the `scoped_thread_local!` macro)
* `Ref::filter_map`
* `RefMut::filter_map`
* `RwLockReadGuard::map`
* `RwLockWriteGuard::map`
* `Condvar::wait_timeout_with`
Closes#27714Closes#27715Closes#27746Closes#27748Closes#27908Closes#29866
In particular, uses of inclusive ranges within the standard library are
still waiting. Slices and collections can be sliced with `usize` and
`Range*<usize>`, but not yet `Range*Inclusive<usize>`.
Also, we need to figure out what to do about `RangeArgument`. Currently
it has `start()` and `end()` methods which are pretty much identical to
`Range::start` and `Range::end`. For the same reason as Range itself,
these methods can't express a range such as `0...255u8` without
overflow. The easiest choice, it seems to me, is either changing the
meaning of `end()` to be inclusive, or adding a new method, say
`last()`, that is inclusive and specifying that `end()` returns `None`
in cases where it would overflow. Changing the semantics would be a
breaking change, but `RangeArgument` is unstable so maybe we should do
it anyway.
The range desugaring does not use the lang items. Hence I did not add
lang items for inclusive ranges. This cleanup commit removes the old
unused ones as well.
Whether the desugaring _should_ use lang items is another question:
see #30809. But if we decide on a strategy there we can add back these
lang items, and new ones for inclusive ranges.
For stage0 we need to keep the attributes as the lang items still exist
even if they are never used.
This is surprisingly not a breaking change. Unused #[lang] attributes do
not even trigger a lint (see #30881).
.copy_from_slice() does the same job of .clone_from_slice(), but the
former is explicitly for Copy elements and calls `memcpy` directly, and
thus is it efficient without optimization too.
Tracking issue: #31756
RFC: rust-lang/rfcs#1467
I've made these unstable for now. Should they be stabilized straight away since we've had plenty of experience with people using the unstable intrinsics?
fmt: Make sure write_fmt's implementation can use write_char
It looks like the Adapter inside write_fmt was never updated to forward
the write_char method.
