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Compound operator expressions #915

Merged
merged 2 commits into from
Jan 14, 2021
Merged

Compound operator expressions #915

merged 2 commits into from
Jan 14, 2021

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Havvy
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@Havvy Havvy commented Dec 27, 2020

This is the final part of #248, split off from #888 since I have questions on this part and don't want to block #888 on it.

Specifically, is this desugaring correct? I asked on Zulip a few weeks ago, but got no definitive answer.

Also, is it possible to have a relative link to a test file?

@Havvy
Compound operator expressions
6a03568 
I don't actually know if the syntactic sugar is correct, so hopefully
the lang team can sign off that it is in-deed correct.

I also don't know if I can link to the test files without linking to
Github, so I'm linking to Github. We could probably make linkcheck
work for these eventually, if needed?
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ehuss commented Dec 27, 2020

I can't answer if this is correct, but reading through it looks good to me (and #888 also still looks good to me).

Also, is it possible to have a relative link to a test file?

It is not. If you want to leave the link in, I think that's fine, but we unfortunately don't currently have the ability to link-check external links, so there is some risk that it will become broken over time.

@Havvy Havvy added A-expressions Area: Expressions New Content Missing features or aspects of language not currently documented. S-needs-reviewer The pull request poses questions that need to be answered by non-maintainers of the reference labels Dec 29, 2020
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Havvy commented Jan 11, 2021

@nikomatsakis Do you have bandwidth to review this?

joshtriplett
joshtriplett reviewed Jan 13, 2021
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src/expressions/operator-expr.md Outdated
<div class="warning">

Warning: The evaluation order of operands swaps depending on the types of the
operands. Try not to write code that depends on the evaluation order of operands
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This seems sufficiently unusual to warrant further elaboration. The text above ("Otherwise, this expression is syntactic sugar ...") doesn't make it clear that because of that sugar, the evaluation order changes.

Suggested change
operands. Try not to write code that depends on the evaluation order of operands
operands: with primitive types the right-hand side will get evaluated first, while with non-primitive types the left-hand side will get evaluated first. Try not to write code that depends on the evaluation order of operands

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Yeah, I think the distinction got lost somewhere in the ten different ways I tried to formulate it before settling on this one. Adding it explicitly to the warning sounds good to me, so I did so.

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joshtriplett commented Jan 13, 2021 •
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I posted one comment seeking further clarification; other than that, this LGTM. r=me with that addressed.

@Havvy Havvy merged commit 4df4225 into rust-lang:master Jan 14, 2021
@Havvy Havvy deleted the ca2 branch January 14, 2021 05:46
@ehuss ehuss mentioned this pull request Jan 25, 2021
Merged
JohnTitor added a commit to JohnTitor/rust that referenced this pull request Jan 26, 2021
@JohnTitor
Rollup merge of rust-lang#81399 - ehuss:update-books, r=ehuss
554f8c3 
Update books

## nomicon

7 commits in a8584998eacdea7106a1dfafcbf6c1c06fcdf925..bbf06ad39d1f45654047e9596b750cc6e6d1b693
2021-01-06 12:49:49 -0500 to 2021-01-22 07:07:31 -0800
- Fix alloc link in exotic-sizes for local docs (rust-lang/nomicon#255)
- Remove TODO
- Fix small punctuation error
- Arc revisions (Clone atomic explanation) (pt2/3(+?))
- Fix Arc Clone
- Arc revisions (pt1/2(+?))
- Simple Arc implementation (without Weak refs)

## reference

5 commits in 50af691f838937c300b47812d0507c6d88c14f97..f02b09eb6e8af340ad1256a54adb7aae2ff3163e
2021-01-12 21:19:20 -0800 to 2021-01-22 01:53:02 -0800
- Fix missing space (rust-lang/reference#941)
- Start documenting name resolution. (rust-lang/reference#937)
- Fix plural and delete spurious words in comparison ops (rust-lang/reference#932)
- Document execution order (rust-lang/reference#888)
- Compound operator expressions (rust-lang/reference#915)

## book

3 commits in ac57a0ddd23d173b26731ccf939f3ba729753275..e724bd826580ff95df48a8533af7dec1080693d4
2021-01-09 14:18:45 -0500 to 2021-01-20 08:19:49 -0600
- Fixes rust-lang/book#2417. Get the index from user input instead of a const. (rust-lang/book#2566)
- Turn off the playground in a bunch more lib.rs inclusions (rust-lang/book#2569)
- Merge pull request rust-lang/book#2567 from rust-lang/rust-1.49

## rust-by-example

1 commits in 03e23af01f0b4f83a3a513da280e1ca92587f2ec..f633769acef68574427a6fae6c06f13bc2199573
2021-01-09 10:20:28 -0300 to 2021-01-13 20:58:25 -0300
- Fixed styling on closure example (rust-lang/rust-by-example#1405)
JohnTitor added a commit to JohnTitor/rust that referenced this pull request Jan 26, 2021
@JohnTitor
Rollup merge of rust-lang#81399 - ehuss:update-books, r=ehuss
9da3608 
Update books

## nomicon

7 commits in a8584998eacdea7106a1dfafcbf6c1c06fcdf925..bbf06ad39d1f45654047e9596b750cc6e6d1b693
2021-01-06 12:49:49 -0500 to 2021-01-22 07:07:31 -0800
- Fix alloc link in exotic-sizes for local docs (rust-lang/nomicon#255)
- Remove TODO
- Fix small punctuation error
- Arc revisions (Clone atomic explanation) (pt2/3(+?))
- Fix Arc Clone
- Arc revisions (pt1/2(+?))
- Simple Arc implementation (without Weak refs)

## reference

5 commits in 50af691f838937c300b47812d0507c6d88c14f97..f02b09eb6e8af340ad1256a54adb7aae2ff3163e
2021-01-12 21:19:20 -0800 to 2021-01-22 01:53:02 -0800
- Fix missing space (rust-lang/reference#941)
- Start documenting name resolution. (rust-lang/reference#937)
- Fix plural and delete spurious words in comparison ops (rust-lang/reference#932)
- Document execution order (rust-lang/reference#888)
- Compound operator expressions (rust-lang/reference#915)

## book

3 commits in ac57a0ddd23d173b26731ccf939f3ba729753275..e724bd826580ff95df48a8533af7dec1080693d4
2021-01-09 14:18:45 -0500 to 2021-01-20 08:19:49 -0600
- Fixes rust-lang/book#2417. Get the index from user input instead of a const. (rust-lang/book#2566)
- Turn off the playground in a bunch more lib.rs inclusions (rust-lang/book#2569)
- Merge pull request rust-lang/book#2567 from rust-lang/rust-1.49

## rust-by-example

1 commits in 03e23af01f0b4f83a3a513da280e1ca92587f2ec..f633769acef68574427a6fae6c06f13bc2199573
2021-01-09 10:20:28 -0300 to 2021-01-13 20:58:25 -0300
- Fixed styling on closure example (rust-lang/rust-by-example#1405)
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