207: Added the ability to collect a stream of results r=yoshuawuyts a=sunjay
As requested here: https://twitter.com/yoshuawuyts/status/1174026374316773377
The standard library has a very useful implementation of `FromIterator` that takes an iterator of `Result<T, E>` values and is able to produce a value of type `Result<Vec<T>, E>`. I asked for this in `async-std` and @yoshuawuyts recommended that I contribute the impl. It turns out that the implementation in the standard library is even more general than I initially thought. It allows any collection that implements `FromIterator` to be collected from an iterator of `Result<T, E>` values. That means that you can collect into `Result<Vec<T>, E>`, `Result<HashSet<T>, E>`, etc.
I wanted to add a similarly generic impl for this crate so we can also support collecting into any collection that implements `FromStream`.
The implementation for this is based heavily on [what exists in `std`](9150f844e2/src/libcore/result.rs (L1379-L1429)). I made a new `result` module since that's where this impl is in `std`. I still wanted to maintain the conventions of this repo, so I copied the `vec` module that @yoshuawuyts created in #125. Much like in that PR, the new `result` module is private.
There is a doctest in the documentation for `collect` that both teaches that this feature exists and tests that it works in some simple cases.
## Documentation Screenshot
Co-authored-by: Sunjay Varma <varma.sunjay@gmail.com>
180: adds stream::fold combinator r=stjepang a=montekki
Fold. Kind of clumsy around the part with the option and moving out of the shared context.
___
Stdlib: https://doc.rust-lang.org/std/iter/trait.Iterator.html#method.fold
Ref: #129
Co-authored-by: Fedor Sakharov <fedor.sakharov@gmail.com>
177: implement DoubleEndedStream r=yoshuawuyts a=yoshuawuyts
Ref #129. This is the most basic version of the `DoubleEndedStream` trait. Because there is no counterpart in `futures-rs` we allow this to be implementable (not sure if we should though?).
This is not a high-priority trait to implement, with probably the most useful addition being the blanket impl over [`std::iter::Fuse`](https://doc.rust-lang.org/std/iter/struct.Fuse.html) (where we should have a `Fuse` counterpart for `Stream` also).
So I'm taking this one step at the time, and this PR introduces just the bare minimum to get things working. Thanks!
r? @stjepang @taiki-e
## Refs
- https://doc.rust-lang.org/std/iter/trait.DoubleEndedIterator.html
- #129
Co-authored-by: Yoshua Wuyts <yoshuawuyts@gmail.com>
