Removes the following methods from `Bitv`:
- `to_vec`: translates a `Bitv` into a bulky `Vec<uint>` of 0's and 1's
replace with: `bitv.iter().map(|b| if b {1} else {0}).collect()`
- `to_bools`: translates a `Bitv` into a `Vec<bool>`
replace with: `bitv.iter().collect()`
- `ones`: internal iterator over all 1 bits in a `Bitv`
replace with: `BitvSet::from_bitv(bitv).iter().advance(fn)`
These methods had specific functionality which can be replicated more
generally by the modern iterator system. (Also `to_vec` was not even
unit tested!)
The argument passed to Vec::grow is the number of elements to grow
the vector by, not the target number of elements. The old `Bitv`
code did the wrong thing, allocating more memory than it needed to.
The internal masking behaviour for `Bitv` is now defined as:
- Any entirely words in self.storage must be all zeroes.
- Any partially used words may have anything at all in their
unused bits.
This means:
- When decreasing self.nbits, care must be taken that any
no-longer-used words are zeroed out.
- When increasing self.nbits, care must be taken that any
newly-unmasked bits are set to their correct values.
- When reading words, care should be taken that the values of
unused bits are not used. (Preferably, use `Bitv::mask_words`
which zeroes them out for you.)
The old behaviour was that every unused bit was always set to
zero. The problem with this is that unused bits are almost never
read, so forgetting to do this will result in very subtle and
hard-to-track down bugs. This way the responsibility for masking
falls on the places which might cause unused bits to be read: for
now, this is only `Bitv::mask_words` and `BitvSet::insert`.
The old `Bitv` structure had two variations: one represented by a vector of
uints, and another represented by a single uint for bit vectors containing
fewer than uint::BITS bits.
The purpose of this is to avoid the indirection of using a Vec, but the
speedup is only available to users who
(a) are storing less than uints::BITS bits
(b) know this when they create the vector (since `Bitv`s cannot be resized)
(c) don't know this at compile time (else they could use uint directly)
Giving such specific users a (questionable) speed benefit at the cost of
adding explicit checks to almost every single bit call, frequently writing
the same method twice and making iteration much much more difficult, does
not seem like a worthwhile tradeoff to me.
Also, rustc does not use Bitv anywhere, only through BitvSet, which does
not have this optimization.
For reference, here is some speed data from before and after this PR:
BEFORE:
test bitv::tests::bench_bitv_big ... bench: 4 ns/iter (+/- 1)
test bitv::tests::bench_bitv_big_iter ... bench: 4858 ns/iter (+/- 22)
test bitv::tests::bench_bitv_big_union ... bench: 507 ns/iter (+/- 35)
test bitv::tests::bench_bitv_set_big ... bench: 6 ns/iter (+/- 1)
test bitv::tests::bench_bitv_set_small ... bench: 6 ns/iter (+/- 0)
test bitv::tests::bench_bitv_small ... bench: 5 ns/iter (+/- 1)
test bitv::tests::bench_bitvset_iter ... bench: 12930 ns/iter (+/- 662)
test bitv::tests::bench_btv_small_iter ... bench: 39 ns/iter (+/- 1)
test bitv::tests::bench_uint_small ... bench: 4 ns/iter (+/- 1)
AFTER:
test bitv::tests::bench_bitv_big ... bench: 5 ns/iter (+/- 1)
test bitv::tests::bench_bitv_big_iter ... bench: 5004 ns/iter (+/- 102)
test bitv::tests::bench_bitv_big_union ... bench: 356 ns/iter (+/- 26)
test bitv::tests::bench_bitv_set_big ... bench: 6 ns/iter (+/- 0)
test bitv::tests::bench_bitv_set_small ... bench: 6 ns/iter (+/- 1)
test bitv::tests::bench_bitv_small ... bench: 4 ns/iter (+/- 1)
test bitv::tests::bench_bitvset_iter ... bench: 12918 ns/iter (+/- 621)
test bitv::tests::bench_btv_small_iter ... bench: 50 ns/iter (+/- 5)
test bitv::tests::bench_uint_small ... bench: 4 ns/iter (+/- 1)
Slice patterns are different from the rest in that a single slice pattern
does not have a distinct constructor if it contains a variable-length subslice
pattern. For example, the pattern [a, b, ..tail] can match a slice of length 2, 3, 4
and so on.
As a result, the decision tree for exhaustiveness and redundancy analysis should
explore each of those constructors separately to determine if the pattern could be useful
when specialized for any of them.
* channel() - #[unstable]. This will likely remain forever
* sync_channel(n: int) - #[unstable with comment]. Concerns have ben raised
about the usage of the term "synchronous channel" because that generally only
applies to the case where n == 0. If n > 0 then these channels are often
referred to as buffered channels.
* Sender::send(), SyncSender::send(), Receiver::recv() - #[experimental]. These
functions directly violate the general guideline of not providing a failing
and non-failing variant. These functions were explicitly selected for being
excused from this guideline, but recent discussions have cast doubt on that
decision. These functions are #[experimental] for now until a decision is made
as they are candidates for removal.
* Sender::send_opt(), SyncSender::send_opt(), Receiver::recv_opt() - #[unstable
with a comment]. If the above no-`_opt` functions are removed, these functions
will be renamed to the non-`_opt` variants.
* SyncSender::try_send(), Receiver::try_recv() - #[unstable with a comment].
These return types of these functions to not follow general conventions. They
are consistent with the rest of the api, but not with the rest of the
libraries. Until their return types are nailed down, these functions are
#[unstable].
* Receiver::iter() - #[unstable]. This will likely remain forever.
* std::com::select - #[experimental]. The functionality is likely to remain in
some form forever, but it is highly unlikely to remain in its current form. It
is unknown how much breakage this will cause if and when the api is
redesigned, so the entire module and its components are all experimental.
* DuplexStream - #[deprecated]. This type is not composable with other channels
in terms of selection or other expected locations. It can also not be used
with ChanWriter and ChanReader, for example. Due to it being only lightly
used, and easily replaced with two channels, this type is being deprecated and
slated for removal.
* Clone for {,Sync}Sender - #[unstable]. This will likely remain forever.
* channel() - #[unstable]. This will likely remain forever
* sync_channel(n: int) - #[unstable with comment]. Concerns have ben raised
about the usage of the term "synchronous channel" because that generally only
applies to the case where n == 0. If n > 0 then these channels are often
referred to as buffered channels.
* Sender::send(), SyncSender::send(), Receiver::recv() - #[experimental]. These
functions directly violate the general guideline of not providing a failing
and non-failing variant. These functions were explicitly selected for being
excused from this guideline, but recent discussions have cast doubt on that
decision. These functions are #[experimental] for now until a decision is made
as they are candidates for removal.
* Sender::send_opt(), SyncSender::send_opt(), Receiver::recv_opt() - #[unstable
with a comment]. If the above no-`_opt` functions are removed, these functions
will be renamed to the non-`_opt` variants.
* SyncSender::try_send(), Receiver::try_recv() - #[unstable with a comment].
These return types of these functions to not follow general conventions. They
are consistent with the rest of the api, but not with the rest of the
libraries. Until their return types are nailed down, these functions are
#[unstable].
* Receiver::iter() - #[unstable]. This will likely remain forever.
* std::com::select - #[experimental]. The functionality is likely to remain in
some form forever, but it is highly unlikely to remain in its current form. It
is unknown how much breakage this will cause if and when the api is
redesigned, so the entire module and its components are all experimental.
* DuplexStream - #[deprecated]. This type is not composable with other channels
in terms of selection or other expected locations. It can also not be used
with ChanWriter and ChanReader, for example. Due to it being only lightly
used, and easily replaced with two channels, this type is being deprecated and
slated for removal.
* Clone for {,Sync}Sender - #[unstable]. This will likely remain forever.
POSIX has recvfrom(2) and sendto(2), but their name seem not to be suitable with Rust. We already renamed getpeername(2) and getsockname(2), so I think it makes sense.
Alternatively, `receive_from` would be fine. However, we have `.recv()` so I chose `recv_from`.
What do you think? If this makes sense, should I provide `recvfrom` and `sendto` deprecated methods just calling new methods for compatibility?
While `HashMap::new` and `HashMap::with_capacity` were being initialized with a random `SipHasher`, it turns out that `HashMap::from_iter` was just using the default instance of `SipHasher`, which wasn't randomized. This closes that bug, and also inlines some important methods.
Being able to index into the bytes of a string encourages
poor UTF-8 hygiene. To get a view of `&[u8]` from either
a `String` or `&str` slice, use the `as_bytes()` method.
Closes#12710.
[breaking-change]
If the diffstat is any indication this shouldn't have a huge impact but it will have some. Most changes in the `str` and `path` module. A lot of the existing usages were in tests where ascii is expected. There are a number of other legit uses where the characters are known to be ascii.
Being able to index into the bytes of a string encourages
poor UTF-8 hygiene. To get a view of `&[u8]` from either
a `String` or `&str` slice, use the `as_bytes()` method.
Closes#12710.
[breaking-change]
Whew. So much here! Feedback very welcome.
This is the first part where we actually start learning things. I'd like to think I struck a good balance of explaining enough details, without getting too bogged down, and without being confusing... but of course I'd think that. 😉
As I mention in the commit comment, We probably want to move the guessing game to the rust-lang org, rather than just having it on my GitHub. Or, I could put the code inline. I think it'd be neat to have it as a project, so people can pull it down with Cargo. Until we make that decision, I'll just leave this here.
Whew! Who knew there was so much to say about variables.
We probably want to move the guessing game to the rust-lang org, rather than
just having it on my GitHub. Or, I could put the code inline. I think it'd be
neat to have it as a project, so people can pull it down with Cargo. Until we
make that decision, I'll just leave this here.
Part of #14248
Main authors:
- @Ryman: OK
- @TeXitoi: OK
- @pcwalton: OK
Minor authors:
- @brson: OK
- @alexcrichton: OK
- @kballard: OK
Remark: @tedhorst was a main contributor, but its contribution
disapear with @pcwalton rewrite at af4ea11
@brson OK?
POSIX has recvfrom(2) and sendto(2), but their name seem not to be
suitable with Rust. We already renamed getpeername(2) and
getsockname(2), so I think it makes sense.
Alternatively, `receive_from` would be fine. However, we have `.recv()`
so I chose `recv_from`.
Signed-off-by: OGINO Masanori <masanori.ogino@gmail.com>
- Fix a couple mistakes:
- `Ordering` is an enum, not a trait.
- `Container` is now named `Collection`.
- Add missing `CheckedDiv`.
- Remove obsolete `OwnedVector`.
- Reorganize some lines to match [prelude's arrangement](http://doc.rust-lang.org/std/prelude/#reexports), making mistakes easier to spot in the future.
I'm going to move testing to be right AFTER the guessing game. I wanted it
to be borderline TDD, but I think that, since the first example is just one
file, it might be a bit overkill.
I'm doing this in its own commit to hopefully avoid merge conflicts.
Earlier commits have established a baseline of `experimental` stability
for all crates under the facade (so their contents are considered
experimental within libstd). Since `experimental` is `allow` by
default, we should use the same baseline stability for libstd itself.
This commit adds `experimental` tags to all of the modules defined in
`std`, and `unstable` to `std` itself.
This does two things:
* Reorganizes the declaration order to be more readable, less random.
* Removes the `slice::traits` module, a public module that does nothing but declare impls of `cmp` traits.
Part of #14248
Main authors:
- @Ryman: OK
- @TeXitoi: OK
- @pcwalton: OK
Minor authors:
- @brson: OK
- @alexcrichton: OK
- @kballard: OK
Remark: @tedhorst was a main contributor, but its contribution
disapear with @pcwalton rewrite at af4ea11
This commit hooks rustdoc into the stability index infrastructure in two
ways:
1. It looks up stability levels via the index, rather than by manual
attributes.
2. It adds stability level information throughout rustdoc output, rather
than just at the top header. In particular, a stability color (with
mouseover text) appears next to essentially every item that appears
in rustdoc's HTML output.
Along the way, the stability index code has been lightly refactored.
Earlier commits have established a baseline of `experimental` stability
for all crates under the facade (so their contents are considered
experimental within libstd). Since `experimental` is `allow` by
default, we should use the same baseline stability for libstd itself.
This commit adds `experimental` tags to all of the modules defined in
`std`, and `unstable` to `std` itself.
This commit hooks rustdoc into the stability index infrastructure in two
ways:
1. It looks up stability levels via the index, rather than by manual
attributes.
2. It adds stability level information throughout rustdoc output, rather
than just at the top header. In particular, a stability color (with
mouseover text) appears next to essentially every item that appears
in rustdoc's HTML output.
Along the way, the stability index code has been lightly refactored.
I'm working on adding examples to the API documentation. Should future pull requests include examples for more than one function? Or is this about the right size for a pull request?
./hello_world is not recognized on Windows.
We can type either hello_world or hello_world.exe to run the executable. I chose "hello_world.exe", which seems more conventional on Windows.
### Breaking changes:
* **Removed unnecessary `box` from enum variant (`Object(Box<Object>)` becomes `Object(Object)`)**
* **Deprecated `Encoder::str_encode`**
### Other changes:
* Tried to make the code more idiomatic
* Renamed the `wr` field of the `Encoder` and `PrettyEncoder` structs to `writer`
* Replaced some `from_utf8` by `from_utf8_owned` to avoid unnecessary allocations
* Removed unnecessary `unsafe` code
* Added `encode` and `decode` shortcut functions
* Implemented `FromStr` for `Json`
* Implemented `ToJson` for tuples of arity up to 12
* Fixed some details in the documentation
### Questions
* ~~The `encode` shortcut function does the same as the `Encoder::str_encode` function. It seems wrong to me that two functions do exactly the same. Should we deprecate `Encoder::str_encode`?~~
* ~~Do we really want the ToJson trait for tuples? At the moment we have it for (), (A, B), (A, B, C). I would like to remove them.~~
* ~~We are using `String` as key in the `TreeMap` representing a `Json` object. It would be better to use `&str`, but this would require to annotate lots of lifetimes. Is there any easy solution for this?~~
* There is a lot of duplicated code (`PrettyEncoder` copies about 50 lines from `Encoder`). In an OO language this could be solved very elegantly by using inheritance and overriding. What can we do here to reduce the amount of boilerplate?
[breaking-change]
