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<p class="MsoNormal">I used to agree with the “always put braces unless it fits on a single line” camp, but it turns out that it’s really hard to break in a debugger on
<span style="font-family:"Courier New"">`statement;` </span>if you write it <span style="font-family:"Courier New"">
`if (cond) statement;`</span><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Personally, I’m in the “always put braces” camp. I think the many advantages to this approach have been stated by many people in this thread. The sole (that I’ve seen mentioned) disadvantage is “clutter”. However, I think in practice you
learn to ignore the excess braces, especially since we write them like this:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">```<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">if (foo) {<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> bar;<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">} else if (baz) {<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> quux;<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">}<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">```<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">That’s only one more line than:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">```<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">if (foo)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> bar;<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">else if (baz)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> quux;<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">```<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I had never mentioned anything because I have traumatic memories of endless arguments about coding style at previous orgs, but I would personally be strongly be in favor of the rule being “always put braces for the bodies of branches and
loops”. Regardless, I think for the purposes of a body being “trivial”, comments on their own line, or statements broken across multiple lines should not be considered trivial:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">```<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">if (foo)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> return nullptr; // this body is trivial<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">if (foo)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> // this body is no longer trivial<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> return nullptr;<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">if (bar)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> GlobalState = <o:p>
</o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> doTheThing(this, body, is, no, longer, trivial);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">```<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks,<o:p></o:p></p>
<p class="MsoNormal"> Christopher Tetreault<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b>From:</b> llvm-dev <llvm-dev-bounces@lists.llvm.org> <b>On Behalf Of
</b>Gabriel Hjort Åkerlund via llvm-dev<br>
<b>Sent:</b> Tuesday, June 16, 2020 1:16 AM<br>
<b>To:</b> jh7370.2008@my.bristol.ac.uk; Matt Arsenault <arsenm2@gmail.com><br>
<b>Cc:</b> llvm-dev@lists.llvm.org<br>
<b>Subject:</b> [EXT] Re: [llvm-dev] Codifying our Brace rules-<o:p></o:p></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-family:"Ericsson Hilda"">I also prefer to always use braces even when not strictly necessary, for the same reasons as already mentioned. The only situation where I personally choose to remove the braces is when the statement
fits on the same line as the condition, e.g.:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Ericsson Hilda""><o:p> </o:p></span></p>
<p class="MsoNormal" style="margin-left:65.2pt"><span style="font-family:"Courier New"">if (cond) statement;<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Ericsson Hilda""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Ericsson Hilda"">In such cases, I find it clear that I need to add braces when expanding the statements.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Ericsson Hilda""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Ericsson Hilda"">But in case we want to be on the safe side I vote for always including braces, no matter what.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Ericsson Hilda""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Ericsson Hilda"">Gabriel <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Ericsson Hilda""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Ericsson Hilda""><o:p> </o:p></span></p>
<p class="MsoNormal"><b>From:</b> llvm-dev <<a href="mailto:llvm-dev-bounces@lists.llvm.org">llvm-dev-bounces@lists.llvm.org</a>>
<b>On Behalf Of </b>James Henderson via llvm-dev<br>
<b>Sent:</b> den 16 juni 2020 10:02<br>
<b>To:</b> Matt Arsenault <<a href="mailto:arsenm2@gmail.com">arsenm2@gmail.com</a>><br>
<b>Cc:</b> llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org">llvm-dev@lists.llvm.org</a>><br>
<b>Subject:</b> Re: [llvm-dev] Codifying our Brace rules-<o:p></o:p></p>
<p class="MsoNormal"><span lang="SV"><o:p> </o:p></span></p>
<div>
<div>
<p class="MsoNormal"><span lang="SV">I'm with Matt on this one. I much prefer the approach of ALWAYS use braces for ifs and for loops, even if they're not needed, for basically the same reasons as he put. The number of times I've added a statement inside an
if without braces and forget to add them is annoyingly high, especially as it's not always an obvious error upfront. Similarly, being involved in a downstream codebase with several private patches, having to sometimes add the braces makes merges all the harder
and sometimes more dangerous.<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="SV"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="SV">I doubt we're going to get the policy changed from "don't include unnecessary braces for trivial statements" but if there's any style that adds them in more places, I'm up for that.<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="SV"><o:p> </o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span lang="SV">James<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><span lang="SV"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="SV">On Mon, 15 Jun 2020 at 20:56, Matt Arsenault via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org">llvm-dev@lists.llvm.org</a>> wrote:<o:p></o:p></span></p>
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<blockquote style="border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt">
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<p class="MsoNormal"><span lang="SV"><o:p> </o:p></span></p>
<div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span lang="SV"><o:p> </o:p></span></p>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<div>
<p class="MsoNormal"><span lang="SV">On Jun 15, 2020, at 15:46, Keane, Erich via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" target="_blank">llvm-dev@lists.llvm.org</a>> wrote:<o:p></o:p></span></p>
</div>
<p class="MsoNormal"><span lang="SV"><o:p> </o:p></span></p>
<div>
<div>
<div>
<p class="MsoNormal"><span lang="SV">Hi all-<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span lang="SV"> <o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span lang="SV">A few weeks ago I noticed that our “omit braces with single line blocks” rule wasn’t written down! Additionally, as a group on IRC and in review, noticed that the enforcement of this rule has been extremely inconsistent.
We made a first run at codifying our existing practice here: <a href="https://protect2.fireeye.com/v1/url?k=9efa459c-c04ad804-9efa0507-861fcb972bfc-42265df8dd683c0d&q=1&e=1cccb19d-3ee2-420f-b3a4-89ab398de655&u=https%3A%2F%2Freviews.llvm.org%2FD80947" target="_blank"><span style="color:#954F72">https://reviews.llvm.org/D80947</span></a>,
which was then committed after significant time on llvm-commits.<o:p></o:p></span></p>
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<div>
<p class="MsoNormal"><span lang="SV"> <o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span lang="SV">I would like to encourage the list via discussion and further reviews/commits to come to a consensus on what we actually MEAN by this rule. For example, a recent comment points out that :<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span lang="SV"> <o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span lang="SV">If (cond)<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span lang="SV"> Stmt;<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span lang="SV">else if (cond)<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span lang="SV"> Stmt;<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span lang="SV">else {<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span lang="SV"> Stmt;<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span lang="SV"> Stmt;<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span lang="SV">}<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span lang="SV"> <o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span lang="SV">Should require braces on all of the conditions! However, we are extraordinarily inconsistent here. My wish is for us to become more consistent, so I would like us to use this thread to organize our collective thoughts
on figuring out what the rule actually SHOULD be, and organizing a handful of commits to the coding standard to make sure it says what we mean.<o:p></o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span lang="SV"><br>
Thanks,<br>
Erich<o:p></o:p></span></p>
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</blockquote>
<p class="MsoNormal"><span lang="SV"><o:p> </o:p></span></p>
</div>
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<p class="MsoNormal"><span lang="SV"><o:p> </o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span lang="SV">I think braces should be added in all contexts, and the more contexts the better. It eliminates any inconsistency or attempt to contextually interpret rules. It also reduces merge conflicts, since something eventually something
will probably be added inside any control flow statement. I’ve suffered through many painful merges trying to find where the braces went wrong, usually due to switch statements. The sometimes-braces-sometimes-not combined with the lack of indentation for switch
cases leads to way more time figuring out braces than should be necessary.<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="SV"><o:p> </o:p></span></p>
</div>
<div>
<p class="MsoNormal"><span lang="SV">-Matt<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><span lang="SV">_______________________________________________<br>
LLVM Developers mailing list<br>
<a href="mailto:llvm-dev@lists.llvm.org" target="_blank">llvm-dev@lists.llvm.org</a><br>
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</blockquote>
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