floating point numbers for real.
This will break code that looks like:
let mut x = 0;
while ... {
x += 1;
}
println!("{}", x);
Change that code to:
let mut x = 0i;
while ... {
x += 1;
}
println!("{}", x);
Closes#15201.
[breaking-change]
This change registers new snapshots, allowing `*T` to be removed from the language. This is a large breaking change, and it is recommended that if compiler errors are seen that any FFI calls are audited to determine whether they should be actually taking `*mut T`.
This PR includes two big things and a bunch of little ones.
1) It enables hygiene for variables bound by 'match' expressions.
2) It fixes a bug discovered indirectly (#15221), wherein fold traversal failed to visit nonterminal nodes.
3) It fixes a small bug in the macro tutorial.
It also adds tests for the first two, and makes a bunch of small comment improvements and cleanup.
This diff will look better once bors takes care of https://github.com/rust-lang/rust/pull/15183
@brson and I talked about it, and, if I commit this skeleton, I can submit PRs for each portion, without doing this silly "builds on previous PRs" stuff, and it shouldn't cause conflicts.
This lays out what I think the guide should cover, and in what order. I haven't picked a cohesive project yet that shows all this off, but I think this progression of concepts is appropriate.
What's funny about this one is that spellcheck caught it, but for
some reason didn't give me the right suggestion, so I assumed that it
wasn't in my dictionary. Oh well.
Thanks @P1start! ❤️
This is built on top of https://github.com/rust-lang/rust/pull/15162 . cccae83d92 is the only new commit, you may want to look at that rather than the whole diff.
Writing our first Rust program together. This is the most crucial step, so I go to a fairly deep level of detail. Future sections will move more quickly.
This has my voice *very strongly*. I'm not sure if it's too much. I'd find it okay if I had to tone it back, and I don't want it to be _too strong_, but clinical docs are boring.
Yes, it is important to be careful, but repeated emphasis about it is probably
not helpful — it starts to sound like you came for a tutorial but found a
finger-wagging lecture.
Even after I removed a few of these comments, there are still several left in
the text. That's probably fine! A couple of mentions of how this is dangerous
and you ought to be careful may be a good reminder to the reader.
After making the edits, I reflowed the paragraphs that I had touched, using
emacs's "M-x fill-paragraph", with fill-column equal to 70.
This is because I observed someone reading the tutorial who thought they'd
missed something when they got to the mention of variable bindings.
This patch doesn't reflow the paragraphs so that you can see the semantic
change that I made, and a subsequent patch will reflow this paragraph.
Fixes https://github.com/rust-lang/rust/issues/13570.
Yes, it is important to be careful, but repeated emphasis about it is probably
not helpful — it starts to sound like you came for a tutorial but found a
finger-wagging lecture.
Even after I removed a few of these comments, there are still several left in
the text. That's probably fine! A couple of mentions of how this is dangerous
and you ought to be careful may be a good reminder to the reader.
After making the edits, I reflowed the paragraphs that I had touched, using
emacs's "M-x fill-paragraph", with fill-column equal to 70.
In line with what @brson, @cmr, @nikomatsakis and I discussed this morning, my
redux of the tutorial will be implemented as the Guide. This way, I can work in
small iterations, rather than dropping a huge PR, which is hard to review. In
addition, the community can observe my work as I'm doing it.
This adds a note in line with [this comment][reddit] that clarifies the state
of the tutorial, and the community's involvement with it.
[reddit]: http://www.reddit.com/r/rust/comments/28bew8/rusts_documentation_is_about_to_drastically/ci9c98k
This breaks a fair amount of code. The typical patterns are:
* `for _ in range(0, 10)`: change to `for _ in range(0u, 10)`;
* `println!("{}", 3)`: change to `println!("{}", 3i)`;
* `[1, 2, 3].len()`: change to `[1i, 2, 3].len()`.
RFC #30. Closes#6023.
[breaking-change]
If you define lang items in your crate, add `#[feature(lang_items)]`.
If you define intrinsics (`extern "rust-intrinsic"`), add
`#[feature(intrinsics)]`.
Closes#12858.
[breaking-change]
This commit makes several changes to the stability index infrastructure:
* Stability levels are now inherited lexically, i.e., each item's
stability level becomes the default for any nested items.
* The computed stability level for an item is stored as part of the
metadata. When using an item from an external crate, this data is
looked up and cached.
* The stability lint works from the computed stability level, rather
than manual stability attribute annotations. However, the lint still
checks only a limited set of item uses (e.g., it does not check every
component of a path on import). This will be addressed in a later PR,
as part of issue #8962.
* The stability lint only applies to items originating from external
crates, since the stability index is intended as a promise to
downstream crates.
* The "experimental" lint is now _allow_ by default. This is because
almost all existing crates have been marked "experimental", pending
library stabilization. With inheritance in place, this would generate
a massive explosion of warnings for every Rust program.
The lint should be changed back to deny-by-default after library
stabilization is complete.
* The "deprecated" lint still warns by default.
The net result: we can begin tracking stability index for the standard
libraries as we stabilize, without impacting most clients.
Closes#13540.
Closes#8142.
This is not the semantics we want long-term. You can continue to use
`#[unsafe_destructor]`, but you'll need to add
`#![feature(unsafe_destructor)]` to the crate attributes.
[breaking-change]
```test_harness
#[test]
fn foo() {}
```
will now compile and run the tests, rather than just ignoring & stripping them (i.e. it is as if `--test` was passed).
Also, the specific example in https://github.com/rust-lang/rust/issues/12242 was fixed (but that issue is broader than that example).
rustdoc now supports compiling things with `--test` so the examples in
this guide can be compiled & tested properly (revealing a few issues &
out-dated behaviours).
Also, reword an example to be clearer, cc #12242.
This adds the `test_harness` directive that runs a code block using the
test runner, to allow for `#[test]` items to be demonstrated and still
tested (currently they are just stripped and not even compiled, let
alone run).
This commit makes several changes to the stability index infrastructure:
* Stability levels are now inherited lexically, i.e., each item's
stability level becomes the default for any nested items.
* The computed stability level for an item is stored as part of the
metadata. When using an item from an external crate, this data is
looked up and cached.
* The stability lint works from the computed stability level, rather
than manual stability attribute annotations. However, the lint still
checks only a limited set of item uses (e.g., it does not check every
component of a path on import). This will be addressed in a later PR,
as part of issue #8962.
* The stability lint only applies to items originating from external
crates, since the stability index is intended as a promise to
downstream crates.
* The "experimental" lint is now _allow_ by default. This is because
almost all existing crates have been marked "experimental", pending
library stabilization. With inheritance in place, this would generate
a massive explosion of warnings for every Rust program.
The lint should be changed back to deny-by-default after library
stabilization is complete.
* The "deprecated" lint still warns by default.
The net result: we can begin tracking stability index for the standard
libraries as we stabilize, without impacting most clients.
Closes#13540.
Replace its usage with byte string literals, except in `bytes!()` tests.
Also add a new snapshot, to be able to use the new b"foo" syntax.
The src/etc/2014-06-rewrite-bytes-macros.py script automatically
rewrites `bytes!()` invocations into byte string literals.
Pass it filenames as arguments to generate a diff that you can inspect,
or `--apply` followed by filenames to apply the changes in place.
Diffs can be piped into `tip` or `pygmentize -l diff` for coloring.
See #14646 (tracking issue) and rust-lang/rfcs#69.
This does not close the tracking issue, as the `bytes!()` macro still needs to be removed. It will be later, after a snapshot is made with the changes in this PR, so that the new syntax can be used when bootstrapping the compiler.
`#[inline(never)]` is used.
Closes#8958.
This can break some code that relied on the addresses of statics
being distinct; add `#[inline(never)]` to the affected statics.
[breaking-change]
Previously, the type system's restrictions on borrowing were summarized as
> The previous example showed that the type system forbids any borrowing of owned boxes found in aliasable, mutable memory.
This did not jive with the example, which allowed mutations so long as the borrowed reference had been returned. Also, the language has changed to no longer allow aliasable mutable locations. This changes the summary to read
> The previous example showed that the type system forbids mutations of owned boxed values while they are being borrowed. In general, the type system also forbids borrowing a value as mutable if it is already being borrowed - either as a mutable reference or an immutable one.
This adds more general information for the experienced reader as well, to offer a more complete understanding.
The guide previously stated:
> The compiler will automatically convert a box box point to a reference like &point.
This fixes the doubled word `box`, so the statement reads
> The compiler will automatically convert a box point to a reference like &point.
The code it is referring to is `compute_distance(&on_the_stack, on_the_heap);`, so a single `box` is appropriate.
This commit is the final step in the libstd facade, #13851. The purpose of this
commit is to move libsync underneath the standard library, behind the facade.
This will allow core primitives like channels, queues, and atomics to all live
in the same location.
There were a few notable changes and a few breaking changes as part of this
movement:
* The `Vec` and `String` types are reexported at the top level of libcollections
* The `unreachable!()` macro was copied to libcore
* The `std::rt::thread` module was moved to librustrt, but it is still
reexported at the same location.
* The `std::comm` module was moved to libsync
* The `sync::comm` module was moved under `sync::comm`, and renamed to `duplex`.
It is now a private module with types/functions being reexported under
`sync::comm`. This is a breaking change for any existing users of duplex
streams.
* All concurrent queues/deques were moved directly under libsync. They are also
all marked with #![experimental] for now if they are public.
* The `task_pool` and `future` modules no longer live in libsync, but rather
live under `std::sync`. They will forever live at this location, but they may
move to libsync if the `std::task` module moves as well.
[breaking-change]
This commit is the final step in the libstd facade, #13851. The purpose of this
commit is to move libsync underneath the standard library, behind the facade.
This will allow core primitives like channels, queues, and atomics to all live
in the same location.
There were a few notable changes and a few breaking changes as part of this
movement:
* The `Vec` and `String` types are reexported at the top level of libcollections
* The `unreachable!()` macro was copied to libcore
* The `std::rt::thread` module was moved to librustrt, but it is still
reexported at the same location.
* The `std::comm` module was moved to libsync
* The `sync::comm` module was moved under `sync::comm`, and renamed to `duplex`.
It is now a private module with types/functions being reexported under
`sync::comm`. This is a breaking change for any existing users of duplex
streams.
* All concurrent queues/deques were moved directly under libsync. They are also
all marked with #![experimental] for now if they are public.
* The `task_pool` and `future` modules no longer live in libsync, but rather
live under `std::sync`. They will forever live at this location, but they may
move to libsync if the `std::task` module moves as well.
[breaking-change]
Previously, the type system's restrictions on borrowing were summarized as
> The previous example showed that the type system forbids any borrowing of owned boxes found in aliasable, mutable memory
This did not jive with the example, which allowed mutations so long as the borrowed reference had been returned. Also, the language has changed to no longer allow aliasable mutable locations. This changes the summary to read
> The previous example showed that the type system forbids mutations of owned boxed values while they are being borrowed. In general, the type system also forbids borrowing a value as mutable if it is already being borrowed - either as a mutable reference or an immutable one.
This adds more general information for the experienced reader as well, to offer a more complete understanding.
The guide previously stated:
> The compiler will automatically convert a box box point to a reference like &point.
This fixes the doubled word `box`, so the statement reads
> The compiler will automatically convert a box point to a reference like &point.
The code it is referring to is `compute_distance(&on_the_stack, on_the_heap);`, so a single `box` is appropriate.
This grows a new option inside of rustdoc to add the ability to submit examples
to an external website. If the `--markdown-playground-url` command line option
or crate doc attribute `html_playground_url` is present, then examples will have
a button on hover to submit the code to the playground specified.
This commit enables submission of example code to play.rust-lang.org. The code
submitted is that which is tested by rustdoc, not necessarily the exact code
shown in the example.
Closes#14654
* null and mut_null are unstable. Their names may change if the unsafe
pointer types change.
* copy_memory and copy_overlapping_memory are unstable. We think they
aren't going to change.
* set_memory and zero_memory are experimental. Both the names and
the semantics are under question.
* swap and replace are unstable and probably won't change.
* read is unstable, probably won't change
* read_and_zero is experimental. It's necessity is in doubt.
* mem::overwrite is now called ptr::write to match read and is
unstable. mem::overwrite is now deprecated
* array_each, array_each_with_len, buf_len, and position are
all deprecated because they use old style iteration and their
utility is generally under question.
Now that rustdoc understands proper language tags
as the code not being Rust, we can tag everything
properly. `norust` as a negative statement is a bad
tag.
This change tags examples in other languages by
their language. Plain notations are marked as `text`.
Console examples are marked as `console`.
Also fix markdown.rs to not highlight non-rust code.
Amends the documentation to reflect the new
behaviour.
Now that rustdoc understands proper language tags
as the code not being Rust, we can tag everything
properly.
This change tags examples in other languages by
their language. Plain notations are marked as `text`.
Console examples are marked as `console`.
Also fix markdown.rs to not highlight non-rust code.
Cross crate links can target items which are not rendered in the documentation.
If the item is reexported at a higher level, the destination of the link (a
concatenation of the fully qualified name) may actually lead to nowhere. This
fixes this problem by altering rustdoc to emit pages which redirect to the local
copy of the reexported structure.
cc #14515Closes#14137
Renamed `owned_box` to `on_the_heap` to use a consistent
naming across the tutorial and the life time guide.
Also it makes the example easier to grasp.
The last example in the containers and iterators guide had a superfluous owned vector in it. Everything works fine without it, so I removed it to avoid confusion.
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 libcore 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.
cc #13851
[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]
According to the corresponding section, accessing a mutable static variable requires `unsafe` too, and I believe it counts as as language level feature. Add it to the relevant list in the Unsafety section.
According to the corresponding section, accessing a mutable static variable requires `unsafe` too, and I believe it counts as as language level feature. Add it to the relevant list in the Unsafety section.
This commit moves reflection (as well as the {:?} format modifier) to a new
libdebug crate, all of which is marked experimental.
This is a breaking change because it now requires the debug crate to be
explicitly linked if the :? format qualifier is used. This means that any code
using this feature will have to add `extern crate debug;` to the top of the
crate. Any code relying on reflection will also need to do this.
Closes#12019
[breaking-change]
This commit moves reflection (as well as the {:?} format modifier) to a new
libdebug crate, all of which is marked experimental.
This is a breaking change because it now requires the debug crate to be
explicitly linked if the :? format qualifier is used. This means that any code
using this feature will have to add `extern crate debug;` to the top of the
crate. Any code relying on reflection will also need to do this.
Closes#12019
[breaking-change]
My main goals were:
- be clear when we talk about "references" and "pointers"
- remove Managed boxes completely and the concept of GC.
https://github.com/mozilla/rust/issues/13987
The current tutorial says that the only way to get master is to build from source, which isn't true anymore - nightly binaries and an installer for Mac OS X are now available at the install page: http://www.rust-lang.org/install.html . Feedback very much welcome! Addresses issue #13578.
As part of the libstd facade (cc #13851), rustdoc is taught to inline documentation across crate boundaries through the usage of a `pub use` statement. This is done to allow libstd to maintain the facade that it is a standalone library with a defined public interface (allowing us to shuffle around what's underneath it).
A preview is available at http://people.mozilla.org/~acrichton/doc/std/index.html
There's a fair number of attributes that have to be whitelisted since
they're either looked for by rustdoc, in trans, or as needed. These can
be cleaned up in the future.
Excluding the functions inherited from the cast module last week (with marked
stability levels), these functions received the following treatment.
* size_of - this method has become #[stable]
* nonzero_size_of/nonzero_size_of_val - these methods have been removed
* min_align_of - this method is now #[stable]
* pref_align_of - this method has been renamed without the
`pref_` prefix, and it is the "default alignment" now. This decision is in line
with what clang does (see url linked in comment on function). This function
is now #[stable].
* init - renamed to zeroed and marked #[stable]
* uninit - marked #[stable]
* move_val_init - renamed to overwrite and marked #[stable]
* {from,to}_{be,le}{16,32,64} - all functions marked #[stable]
* swap/replace/drop - marked #[stable]
* size_of_val/min_align_of_val/align_of_val - these functions are marked
#[unstable], but will continue to exist in some form. Concerns have been
raised about their `_val` prefix.
Excluding the functions inherited from the cast module last week (with marked
stability levels), these functions received the following treatment.
* size_of - this method has become #[stable]
* nonzero_size_of/nonzero_size_of_val - these methods have been removed
* min_align_of - this method is now #[stable]
* pref_align_of - this method has been renamed without the
`pref_` prefix, and it is the "default alignment" now. This decision is in line
with what clang does (see url linked in comment on function). This function
is now #[stable].
* init - renamed to zeroed and marked #[stable]
* uninit - marked #[stable]
* move_val_init - renamed to overwrite and marked #[stable]
* {from,to}_{be,le}{16,32,64} - all functions marked #[stable]
* swap/replace/drop - marked #[stable]
* size_of_val/min_align_of_val/align_of_val - these functions are marked
#[unstable], but will continue to exist in some form. Concerns have been
raised about their `_val` prefix.
[breaking-change]
The core library in theory has 0 dependencies, but in practice it has some in
order for it to be efficient. These dependencies are in the form of the basic
memory operations provided by libc traditionally, such as memset, memcmp, etc.
These functions are trivial to implement and themselves have 0 dependencies.
This commit adds a new crate, librlibc, which will serve the purpose of
providing these dependencies. The crate is never linked to by default, but is
available to be linked to by downstream consumers. Normally these functions are
provided by the system libc, but in other freestanding contexts a libc may not
be available. In these cases, librlibc will suffice for enabling execution with
libcore.
cc #10116
This is to clarify that match construct doesn't define a new variable, since I
observed a person reading the Rust tutorial who seemed to incorrectly think
that it did. Fixes https://github.com/mozilla/rust/issues/13571 .
There are no arrays in Rust, they are slices. Especially in the tutorial beginners should not be confused with wrong terminology. It helps to know the right names for things when you want to find something in the documentation.
@erickt explained that today to me and it helped me a lot when getting started 😉 Maybe we should also explain what a slice and what a vector is in the tutorial. If you like that, I will try to do that and attach that to the pull request 😉
This commit revisits the `cast` module in libcore and libstd, and scrutinizes
all functions inside of it. The result was to remove the `cast` module entirely,
folding all functionality into the `mem` module. Specifically, this is the fate
of each function in the `cast` module.
* transmute - This function was moved to `mem`, but it is now marked as
#[unstable]. This is due to planned changes to the `transmute`
function and how it can be invoked (see the #[unstable] comment).
For more information, see RFC 5 and #12898
* transmute_copy - This function was moved to `mem`, with clarification that is
is not an error to invoke it with T/U that are different
sizes, but rather that it is strongly discouraged. This
function is now #[stable]
* forget - This function was moved to `mem` and marked #[stable]
* bump_box_refcount - This function was removed due to the deprecation of
managed boxes as well as its questionable utility.
* transmute_mut - This function was previously deprecated, and removed as part
of this commit.
* transmute_mut_unsafe - This function doesn't serve much of a purpose when it
can be achieved with an `as` in safe code, so it was
removed.
* transmute_lifetime - This function was removed because it is likely a strong
indication that code is incorrect in the first place.
* transmute_mut_lifetime - This function was removed for the same reasons as
`transmute_lifetime`
* copy_lifetime - This function was moved to `mem`, but it is marked
`#[unstable]` now due to the likelihood of being removed in
the future if it is found to not be very useful.
* copy_mut_lifetime - This function was also moved to `mem`, but had the same
treatment as `copy_lifetime`.
* copy_lifetime_vec - This function was removed because it is not used today,
and its existence is not necessary with DST
(copy_lifetime will suffice).
In summary, the cast module was stripped down to these functions, and then the
functions were moved to the `mem` module.
transmute - #[unstable]
transmute_copy - #[stable]
forget - #[stable]
copy_lifetime - #[unstable]
copy_mut_lifetime - #[unstable]
[breaking-change]
Especially in the tutorial beginners should not be confused with
wrong terminology. It helps to know the right names for things
when you want to find something in the documentation.
Attribute grammar in reference manual allowed `#[foo, bar]`, which does not match parser behavior.
Also rename nonterminals to match parser code.
Fix#13825.
for `~str`/`~[]`.
Note that `~self` still remains, since I forgot to add support for
`Box<self>` before the snapshot.
r? @brson or @alexcrichton or whoever
