Refactored declaring multiple variables on a single line

[Jean Philippe (JeanPhilippeKernel)]

Description

Fixes #522.

Checklist

Be sure you've read README.md and understand the scope of this repo.

If you're unsure about a box, leave it unchecked. A maintainer will help you.

• Identifiers in product code changes are properly _Ugly as per
  https://eel.is/c++draft/lex.name#3.1 or there are no product code changes.
• The STL builds successfully and all tests have passed (must be manually
  verified by an STL maintainer before automated testing is enabled on GitHub,
  leave this unchecked for initial submission).
• These changes introduce no known ABI breaks (adding members, renaming
  members, adding virtual functions, changing whether a type is an aggregate
  or trivially copyable, etc.).
• These changes were written from scratch using only this repository,
  the C++ Working Draft (including any cited standards), other WG21 papers
  (excluding reference implementations outside of proposed standard wording),
  and LWG issues as reference material. If they were derived from a project
  that's already listed in NOTICE.txt, that's fine, but please mention it.
  If they were derived from any other project (including Boost and libc++,
  which are not yet listed in NOTICE.txt), you must mention it here,
  so we can determine whether the license is compatible and what else needs
  to be done.

[Billy O'Neal (BillyONeal)]

Are the llvm-project bits changes intentional?

[Jean Philippe (JeanPhilippeKernel)]

Oop nope:( ! I think It changed when I pulled from STL/master to mine

[Stephan T. Lavavej (StephanTLavavej)]

Looks good, thank you! I observe that the /* const */ comments in ymath.h are being dropped, but that's fine (those variables should be const, but we can't do that because of binary compatibility; in vNext the entire area needs to be completely overhauled so we don't need additional reminders).

I'll go ahead and port this to the Microsoft-internal repo so we can merge it.

One comment about your PRs - if you look at the PR history, it shows a long sequence of commits (17 in this case), with your previous fixes and merges from master. Working in a long-lived branch is fine, but when you submit a new PR, I recommend creating a fresh branch, based on top of the current origin/master, containing one or more commits that are purely for that specific PR. (Usually one squashed commit is best for your initial PR, but it can be structured as a sequence of commits if your changes are unusually complicated; that is, commits in a PR should be arranged for clarity to reviewers, and not as a literal record of history.)

git experts can probably explain better techniques for squashing commits, but what I do is git rebase -i master when that works. When it doesn't (e.g. due to complicated merge history), what I do is:

S:\GitHub\STL>git checkout master
Switched to branch 'master'
Your branch is up to date with 'origin/master'.

S:\GitHub\STL>git pull
Already up to date.

S:\GitHub\STL>git checkout fix-avoid-declaring-multiple-var
Switched to a new branch 'fix-avoid-declaring-multiple-var'
Branch 'fix-avoid-declaring-multiple-var' set up to track remote branch 'fix-avoid-declaring-multiple-var' from 'jeanphilippekernel'.

S:\GitHub\STL>git merge master
Merge made by the 'recursive' strategy.
 llvm-project                                       |   2 +-
 stl/inc/future                                     |  11 +--
[... more output ...]
 35 files changed, 341 insertions(+), 214 deletions(-)

S:\GitHub\STL>git checkout master
Switched to branch 'master'
Your branch is up to date with 'origin/master'.

S:\GitHub\STL>git checkout -b GH-550
Switched to a new branch 'GH-550'

S:\GitHub\STL>git diff master fix-avoid-declaring-multiple-var > C:\Temp\GH-550.patch

S:\GitHub\STL>git apply C:\Temp\GH-550.patch

S:\GitHub\STL>git add --all

S:\GitHub\STL>git commit -m "GH-550 Refactored declaring multiple variables on a single line"
[GH-550 bf5a8a4] GH-550 Refactored declaring multiple variables on a single line
 11 files changed, 86 insertions(+), 38 deletions(-)

This is part of my process for porting changes from GitHub to Microsoft-internal git, but it can also be used to create PRs with simplified history.

[Jean Philippe (JeanPhilippeKernel)]

Oh great !! Thank you so much for the technique !!!
I was looking for a way to do something like that !

[Billy O'Neal (BillyONeal)]

If you aren't transferring between repos the diff/apply step can be reduced to reset, assuming you are already on your branch that you're trying to submit:

    git fetch
    git merge origin/master
    git submodule update
    git reset origin/master
    git commit -am "GH-550 Refactored declaring multiple variables on a single line"

[Stephan T. Lavavej (StephanTLavavej)]

Jean Philippe (@JeanPhilippeKernel) - thanks for improving the codebase yet again. :-)

Billy O'Neal (@BillyONeal) - oh, that makes even more sense, thanks for teaching us.

[Jean Philippe (JeanPhilippeKernel)]

It's my pleasure and I feel so honored to work with y'all :)
you're an amazing team !! I learn a lot !