This is part of the ongoing renaming of the equality traits. See #12517 for more
details. All code using Eq/Ord will temporarily need to move to Partial{Eq,Ord}
or the Total{Eq,Ord} traits. The Total traits will soon be renamed to {Eq,Ord}.
cc #12517
[breaking-change]
This commit shuffles around some of the `rand` code, along with some
reorganization. The new state of the world is as follows:
* The librand crate now only depends on libcore. This interface is experimental.
* The standard library has a new module, `std::rand`. This interface will
eventually become stable.
Unfortunately, this entailed more of a breaking change than just shuffling some
names around. The following breaking changes were made to the rand library:
* Rng::gen_vec() was removed. This has been replaced with Rng::gen_iter() which
will return an infinite stream of random values. Previous behavior can be
regained with `rng.gen_iter().take(n).collect()`
* Rng::gen_ascii_str() was removed. This has been replaced with
Rng::gen_ascii_chars() which will return an infinite stream of random ascii
characters. Similarly to gen_iter(), previous behavior can be emulated with
`rng.gen_ascii_chars().take(n).collect()`
* {IsaacRng, Isaac64Rng, XorShiftRng}::new() have all been removed. These all
relied on being able to use an OSRng for seeding, but this is no longer
available in librand (where these types are defined). To retain the same
functionality, these types now implement the `Rand` trait so they can be
generated with a random seed from another random number generator. This allows
the stdlib to use an OSRng to create seeded instances of these RNGs.
* Rand implementations for `Box<T>` and `@T` were removed. These seemed to be
pretty rare in the codebase, and it allows for librand to not depend on
liballoc. Additionally, other pointer types like Rc<T> and Arc<T> were not
supported. If this is undesirable, librand can depend on liballoc and regain
these implementations.
* The WeightedChoice structure is no longer built with a `Vec<Weighted<T>>`,
but rather a `&mut [Weighted<T>]`. This means that the WeightedChoice
structure now has a lifetime associated with it.
* The `sample` method on `Rng` has been moved to a top-level function in the
`rand` module due to its dependence on `Vec`.
cc #13851
[breaking-change]
This commit moves all possible functionality from the standard library's string
formatting utilities into the core library. This is a breaking change, due to a
few tweaks in the semantics of formatting:
1. In order to break the dependency on the std::io module, a new trait,
FormatWriter was introduced in core::fmt. This is the trait which is used
(instead of Writer) to format data into a stream.
2. The new FormatWriter trait has one method, write(), which takes some bytes
and can return an error, but the error contains very little information. The
intent for this trait is for an adaptor writer to be used around the standard
library's Writer trait.
3. The fmt::write{,ln,_unsafe} methods no longer take &mut io::Writer, but
rather &mut FormatWriter. Since this trait is less common, all functions were
removed except fmt::write, and it is not intended to be invoked directly.
The main API-breaking change here is that the fmt::Formatter structure will no
longer expose its `buf` field. All previous code writing directly to `f.buf`
using writer methods or the `write!` macro will now instead use `f` directly.
The Formatter object itself implements the `Writer` trait itself for
convenience, although it does not implement the `FormatWriter` trait. The
fallout of these changes will be in the following commits.
[breaking-change]
