Add a chain! macro. #525
Add a chain! macro. #525
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tests/quick.rs Outdated
| fn size_chain_macro(a: Iter<i16, Exact>, b: Iter<i16, Exact>, c: Iter<i16, Exact>) -> bool { | ||
| correct_size_hint(chain!(a.clone(), b.clone(), c.clone())) | ||
| } |
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I hope I don't miss anything, but is size_hint special for chain!? What about other potentially specialized methods?
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It is not special. I guess this test shouldn't be there (I juste copied some of the izip! tests) since it tests more the properties of the std chain: we don't specialize any method in this crate. I don't see how the macro could be wrong while chain being correct.
If we were to verify all the methods that are specialized by Chain, that would mean writing quite many tests (here is the list).
The chain! macro creates an iterator running multiple iterators sequentially.
| @phimuemue I believe this is ready for a second review. |
| Note: I did not test this, but it looks good to me. As far as I can see, one can call As I do not have that much time to review this, I'd appreciate a second pair eyes on this, to rule out potential pitfalls. |
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Thanks for the PR, and sorry for being so slow at reviewing; I've been super tied up lately.
I wonder if it might also make sense to provide a Chain! type macro that expands to the type produced by chain!, but that doesn't have to be in this PR. I think it might be somewhat tricky to implement, too...
Co-authored-by: Jack Wrenn <me@jswrenn.com>
| @jswrenn Thanks for the suggestions ! |
| Build succeeded: |
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This is proposal to add a
chain!macro which creates an iterator running multiple iterators sequentially.It basically calls multiple times the standard
.chain(). This macro is useful to avoid rightwards shift of the code when chaining many iterators.For the implementation and tests, I took inspiration on the
izip!macro.