Addressing issue #6037, this Scheme-style conditional helps to improve code clarity in instances where the `if`, `else if`, and `else` keywords obscure predicates undesirably.
Here is an example:
~~~rust
let clamped =
if x > mx { mx }
else if x < mn { mn }
else { x };
~~~
Using `cond!`, the above could be written as:
~~~rust
let clamped = cond!(
(x > mx) { mx }
(x < mn) { mn }
_ { x }
);
~~~
The optional default case is denoted by `_`.
I have altered `std::fun_treemap` to demonstrate it in use. I am definitely interested in using it for some of the numeric functions, but I will have to wait for it to reach `stage0` first.
`std::ratio` module contains `BigRational` type, but the type is not usable by following reasons.
* `Ratio::new` requires `T: Copy + Num + Ord`, but `BigInt` is not implicitly copyable, because it contains unique vector.
* `BigInt` is not implements `Num`
So, I rewrite `Ratio` as follows.
* `Ratio` requires `T: Clone + Integer + Ord`.
* `Copy` -> `Clone`: to be able to use `BigRational`
* `Num` -> `Integer`: It is incorrect that a rational number constructed by two non-integer numbers.
* `BigInt` implements `Num` and `Orderable` which are required by `Integer` bound
* They didn't work before, because the location of the tests caused the
'sysroot' option to crate lookup to be wrong for finding the correct stage's
core/std libraries. This moves the compiled tests from the $host/test
directory into a $host/$stage/test directory. This means that the sysroot will
be correct and the core/std libraries can actually be found
* The LLVM bindings apparently aren't threadsafe, so we can't run multiple tests
in parallel.
fail!() used to require owned strings but can handle static strings
now. Also, it can pass its arguments to fmt!() on its own, no need for
the caller to call fmt!() itself.
Also fix up all the fallout elsewhere throughout core. It's really nice being
able to have the prelude.
I'm not quite sure how resolution works with traits, but it seems to me like the public imports at the top-level of the core crate were leaking into the sub-crates, but that could also be working as intended. Regardless, things compile without the re-exports now.
r? @pcwalton
* Move `SharedMutableState`, `LittleLock`, and `Exclusive` from `core::unstable` to `core::unstable::sync`
* Modernize the `SharedMutableState` interface with methods
* Rename `SharedMutableState` to `UnsafeAtomicRcBox` to match `RcBox`.
When trying to import nonexistent items from existing modules, specify that
that is what happened, rather than just reporting "unresolved name".
Ideally the error would be reported on the span of the import... but I do not see a way to get a span there. Help appreciated 😄
This pull request adds 4 atomic intrinsics to the compiler, in preparation for #5042.
* `atomic_load(src: &int) -> int` performs an atomic sequentially consistent load.
* `atomic_load_acq(src: &int) -> int` performs an atomic acquiring load.
* `atomic_store(dst: &mut int, val: int)` performs an atomic sequentially consistent store.
* `atomic_store_rel(dst: &mut int, val: int)` performs an atomic releasing store.
For more information about the whole acquire/release thing: http://llvm.org/docs/Atomics.html
r?
