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Re: Understanding &&

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On 17/04/2021 02:01, Ben Bacarisse wrote:
> Jon Ribbens <jon+usenet@unequivocal.eu> writes:
> 
>> On 2021-04-16, Ben Bacarisse <ben.usenet@bsb.me.uk> wrote:
>>> Jon Ribbens <jon+usenet@unequivocal.eu> writes:
>>>> On 2021-04-16, Ben Bacarisse <ben.usenet@bsb.me.uk> wrote:
>>>>> Jon Ribbens <jon+usenet@unequivocal.eu> writes:
>>>>>> You most often see this sort of thing in JavaScript that was
>>>>>> automatically generated by a compiler (either because the original
>>>>>> source was in something else like TypeScript or a more modern version
>>>>>> of JavaScript or because the author wanted to compress/minify the
>>>>>> script), but human beings are also quite capable of writing hard-to-read
>>>>>> code like this.
>>>>>
>>>>> Is that specifically when the right-hand operand is an assignment
>>>>> expression?  I don't find that hard to read but then I'm used to
>>>>> assignment being and expression so it seems like a natural extension of
>>>>> the more frequently seen uses of &&.
>>>>
>>>> I mean where it's an expression being abused as a control flow
>>>> mechanism.
>>>
>>> If readability is not the problem I'm not sure what constitutes abuse.
>>
>> You snipped the next lines of my post where I said that readability
>> *is* the problem.
> 
> Oh, sorry.  The fact that you didn't address my questions about
> readability made me think you were now making a broader point.  If you
> don't mind, can say if the problems you have with its readability is
> down to there being an assignment on the right, or is it with any use of
> && that relies on the short-circuit evaluation.
> 
>>> Is it just a rule of yours to keep these two things entirely separate?
>>
>> It's not a rule of mine, it seems to be a rule of almost everyone.
> 
> The trouble is that a non-trivial number of languages have this form,
> and I've seen it used quite widely.  But maybe most of the uses don't
> rise to your standard of abuse.  I've not come across the rule, but then
> it's a long time since I worked anywhere that had rules about
> programming.
> 
>>> Maybe some uses are acceptable and don't constitute abuse?  Is any
>>> reliance on short-circuit evaluation in an expression an abuse?
>>
>> No, of course not. I think it's "abuse" because it's written to look
>> like an expression but it isn't, really - we don't care about its
>> result, we only care about its side-effects.
> 
> Ah, right.  So the abuse (as you see it) is not exactly the control flow
> but using it to control side-effects.
> 
> I've seen (and, dare I say, written) code that uses the result.  I
> wonder if that absolves the programmer from the charge of abuse:
> 
>    return (data = parse_input(file_name))
>        && (result = transform(data))
>        && write_file(file_name);
> 
> <cut>
>>> I only suggested that assignment might be where it crosses the line for
>>> you because I think that's where the line is for a lot of people, but it
>>> sounds like go further than that.
>>
>> Maybe it is there. Fundamentally the issue is that if you're going to
>> sacrifice readability, you'd better be getting something good in return.
>> In the case we're talking about some readability has been sacrificed and
>> we've gained absolutely nothing in return - the code isn't shorter, or
>> neater, and it doesn't run faster.
> 
> I don't have any problem with the readability, in general.  Obviously
> you can make unreadable examples, but I not a fan of rules than ban
> something because of the potential for abuse.
> 
U=I can even say why I dont like it.

It mixes up logical comparison with program flow in a single operator.
IF... THEN separates them in an easily read way.
and given modern compiler smarts, terse unintelligible code (like 
rexgexps) simply is unnecessary

-- 
You can get much farther with a kind word and a gun than you can with a 
kind word alone.

Al Capone

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Thread

Understanding && Andrew Poulos <ap_prog@hotmail.com> - 2021-04-16 14:30 +1000
  Re: Understanding && Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-04-16 11:00 +0100
  Re: Understanding && Jon Ribbens <jon+usenet@unequivocal.eu> - 2021-04-16 11:17 +0000
    Re: Understanding && Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-04-16 16:09 +0100
      Re: Understanding && Jon Ribbens <jon+usenet@unequivocal.eu> - 2021-04-16 15:26 +0000
        Re: Understanding && Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-04-16 21:09 +0100
          Re: Understanding && Jon Ribbens <jon+usenet@unequivocal.eu> - 2021-04-16 21:06 +0000
            Re: Understanding && Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-04-17 02:01 +0100
              Re: Understanding && The Natural Philosopher <tnp@invalid.invalid> - 2021-04-17 08:33 +0100
              Re: Understanding && John G Harris <niam@jghnorth.org.uk.invalid> - 2021-04-17 12:06 +0100
                Re: Understanding && The Natural Philosopher <tnp@invalid.invalid> - 2021-04-17 14:13 +0100
                Re: Understanding && Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-04-17 15:50 +0100
              Re: Understanding && Jon Ribbens <jon+usenet@unequivocal.eu> - 2021-04-17 15:21 +0000
                Re: Understanding && Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-04-17 23:46 +0100
                Re: Understanding && Jon Ribbens <jon+usenet@unequivocal.eu> - 2021-04-17 23:46 +0000
                Re: Understanding && Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-04-18 23:59 +0100
                Re: Understanding && Jon Ribbens <jon+usenet@unequivocal.eu> - 2021-04-19 13:56 +0000
                Re: Understanding && Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-04-19 23:08 +0100
                Re: Understanding && Jon Ribbens <jon+usenet@unequivocal.eu> - 2021-04-19 22:52 +0000
                Re: Understanding && Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-04-20 01:23 +0100
                Re: Understanding && Jon Ribbens <jon+usenet@unequivocal.eu> - 2021-04-20 01:08 +0000
              Re: Understanding && Arno Welzel <usenet@arnowelzel.de> - 2021-04-18 00:49 +0200
                Re: Understanding && Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-04-18 17:26 +0100
          Re: Understanding && Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2021-04-17 17:05 +0200
            Re: Understanding && Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-04-17 23:04 +0100
              Re: Understanding && Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2021-04-18 00:48 +0200
                Re: Understanding && Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-04-18 17:13 +0100
                Re: Understanding && Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2021-04-19 21:58 +0200
            Re: Understanding && John G Harris <niam@jghnorth.org.uk.invalid> - 2021-04-18 18:20 +0100
          Re: Understanding && Arno Welzel <usenet@arnowelzel.de> - 2021-04-18 00:40 +0200
            Re: Understanding && Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-04-18 00:14 +0100
              Re: Understanding && Jon Ribbens <jon+usenet@unequivocal.eu> - 2021-04-18 00:01 +0000
                Re: Understanding && Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-04-18 17:44 +0100
                Re: Understanding && Jon Ribbens <jon+usenet@unequivocal.eu> - 2021-04-18 17:51 +0000
              Re: Understanding && Arno Welzel <usenet@arnowelzel.de> - 2021-04-19 13:41 +0200
                Re: Understanding && John G Harris <niam@jghnorth.org.uk.invalid> - 2021-04-19 15:02 +0100
                Re: Understanding && The Natural Philosopher <tnp@invalid.invalid> - 2021-04-20 17:40 +0100
                Re: Understanding && John G Harris <niam@jghnorth.org.uk.invalid> - 2021-04-20 18:19 +0100
                Re: Understanding && The Natural Philosopher <tnp@invalid.invalid> - 2021-04-21 10:11 +0100
                Re: Understanding && John G Harris <niam@jghnorth.org.uk.invalid> - 2021-04-21 19:46 +0100
                Re: Understanding && The Natural Philosopher <tnp@invalid.invalid> - 2021-04-22 13:48 +0100
                Re: Understanding && Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-04-19 21:28 +0100
                Re: Understanding && Jon Ribbens <jon+usenet@unequivocal.eu> - 2021-04-19 21:56 +0000
                Re: Understanding && Ben Bacarisse <ben.usenet@bsb.me.uk> - 2021-04-19 23:13 +0100

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