This enables `num_milliseconds` to return an `i64` again instead of
`Option<i64>`, because it is guaranteed not to overflow.
The Duration range is now rougly 300e6 years (positive and negative),
whereas it was 300e9 years previously. To put these numbers in
perspective, 300e9 years is about 21 times the age of the universe
(according to Wolfram|Alpha). 300e6 years is about 1/15 of the age of
the earth (according to Wolfram|Alpha).
Pros:
I like this example because it's concise without being trivial. The Monty Hall example code is somewhat lengthy and possibly inaccessible to those unfamiliar with probability.
Cons:
The Monty Hall example already exists. Do we need another example? Also, this is probably inaccessible to people who don't know basic geometry.
int/uint aren't considered FFI safe, replace them with the actual type they
represent (i64/u64 or i32/u32). This is a breaking change, but at most a cast
to `uint` or `int` needs to be added.
[breaking-change]
As of RFC 18, struct layout is undefined. Opting into a C-compatible struct
layout is now down with #[repr(C)]. For consistency, specifying a packed
layout is now also down with #[repr(packed)]. Both can be specified.
To fix errors caused by this, just add #[repr(C)] to the structs, and change
#[packed] to #[repr(packed)]
Closes#14309
[breaking-change]
The last two sections of the guide, and a small conclusion. I suck at conclusions.
I also realized I never covered strings, so I'm going to put that section up before we're actually 'done.'
This changes the internal representation of `Duration` from
days: i32,
secs: i32,
nanos: u32
to
secs: i64,
nanos: i32
This resolves#16466. Some methods now take `i64` instead of `i32` due
to the increased range. Some methods, like `num_milliseconds`, now
return an `Option<i64>` instead of `i64`, because the range of
`Duration` is now larger than e.g. 2^63 milliseconds.
There is a check in TwoWaySearcher::new to determine whether the needle
is periodic. This is needed because during searching when a match fails,
we cannot advance the position by the entire length of the needle when
it is periodic, but can only advance by the length of the period.
The reason "bananas".contains("nana") (and similar searches) were
returning false was because the periodicity check was wrong.
Closes#16589
This appears to be a minor typo. This example implies that x is mutable otherwise the compiler would error on the line before the comment implies.
Please let me know if I'm missing something - I'd love to learn what I got wrong!
It's unfortunate that the read+write operands need special treatment in the AST. A separate vec for all expressions is an alternative, but it doesn't play nicely with trans.
Fixes#14936
