Re: cleaning perl code

> On Apr 11, 2020, at 9:47 AM, Andrew Dunstan <andrew(dot)dunstan(at)2ndquadrant(dot)com> wrote:
>
>
> On 4/11/20 12:28 PM, Mark Dilger wrote:
>>
>>> On Apr 11, 2020, at 9:13 AM, Andrew Dunstan <andrew(dot)dunstan(at)2ndquadrant(dot)com> wrote:
>> Hi Andrew. I appreciate your interest and efforts here. I hope you don't mind a few questions/observations about this effort:
>
>
> Not at all.
>
>
>>
>>> The
>>> last one fixes the mixture of high and low precedence boolean operators,
>> I did not spot examples of this in your diffs, but I assume you mean to prohibit conditionals like:
>>
>> if ($a || $b and $c || $d)
>>
>> As I understand it, perl introduced low precedence operators precisely to allow this. Why disallow it?
>
>
> The docs say:
>
>
> Conway advises against combining the low-precedence booleans ( |and
> or not| ) with the high-precedence boolean operators ( |&& || !| )
> in the same expression. Unless you fully understand the differences
> between the high and low-precedence operators, it is easy to
> misinterpret expressions that use both. And even if you do
> understand them, it is not always clear if the author actually
> intended it.
>
> |next| |if| |not ||$foo| ||| ||$bar||; ||#not ok|
> |next| |if| |!||$foo| ||| ||$bar||; ||#ok|
> |next| |if| |!( ||$foo| ||| ||$bar| |); ||#ok|

I don't think any of those three are ok, from a code review perspective, but it's not because high and low precedence operators were intermixed.

>>
>>> and the use of commas to separate statements
>> I don't understand the prejudice against commas used this way. What is wrong with:
>>
>> $i++, $j++ if defined $k;
>>
>> rather than:
>>
>> if (defined $k)
>> {
>> $i++;
>> $j++;
>> }
>>
>
>
> I don't think the example is terribly clear. I have to look at it and
> think "Does it do $i++ if $k isn't defined?"

It works like the equivalent C-code:

if (k)
i++, j++;

which to my eyes is also fine.

I'm less concerned with which perlcritic features you enable than I am with accidentally submitting perl which looks fine to me but breaks the build. I mostly use perl from within TAP tests, which I run locally before submission to the project. Can your changes be integrated into the TAP_TESTS makefile target so that I get local errors about this stuff and can fix it before submitting a regression test to -hackers?

—
Mark Dilger
EnterpriseDB: http://www.enterprisedb.com
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