Cubist's first bug report

Dar Scott dsc at swcp.com
Sun Jun 5 14:42:01 EDT 2016


Very nice and clean example code.  

Also, as you hinted, this does have the problem:
	add 1 to item random(16) of myVar

I infer from this that the problem is very likely not in how 'any' counts items.  

This also applies to subtract and multiply.  I suspect that random(16) is being evaluated twice based on a first glance at the pattern.  Because of that, my guess is that this bug will not cause a crash.  

The problem also occurs when I use my own random function.  

it looks as though this...
	add 1 to any item of x
... is being evaluated as...
	put 1 + any item of x into any item of x
... which is incorrect.

Perhaps that is just the info needed for a quick fix.  

This also will show up for any function with side effects built-in or not, so this is a far ranging bug and it should be pushed up in priority.  

Dar


> On Jun 5, 2016, at 8:48 AM, Mark Schonewille <m.schonewille at economy-x-talk.com> wrote:
> 
> Hi Quentin,
> 
> I see the same results, when I try your code. However, if I first store the random value and add 1 to an item in the string in the next line in the script, it works correctly. Apparently, the random function and the add command are incompatible.
> 
> on mouseUp
>   put "0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0" into myVar
>   repeat 100
>      put random(16) into myRandom
>      add 1 to item myRandom of myVar
>      put myVar & cr after myTempList
>   end repeat
>   put sum(myVar) & cr & myTempList
> end mouseUp
> 
> Kind regards,
> 
> Mark Schonewille
> http://economy-x-talk.com
> https://www.facebook.com/marksch
> 
> Buy the most extensive book on the
> LiveCode language:
> http://livecodebeginner.economy-x-talk.com
> 
> Op 05-Jun-16 om 16:12 schreef Quentin Long:
>> Code which exhibits the bug:
>> 
>> on mouseUp
>>   put "0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0" into Fred
>>   repeat 100 times
>>      add 1 to any item of Fred
>>      put Fred into line (1 + the number of lines in fld "testbed") of fld "testbed"
>>   end repeat
>>   put sum (Fred) into line (1 + the number of lines in fld "testbed") of fld "testbed"
>> end mouseUp
>> 
>> This handler *should* end up generating a 16-item string of integers which sum to exactly 100. What it *actually does* end up generating, is a 16-item string of integers whose sum may or may not fall somewhere within the range 80-120. Not sure what the hell is going on here, but I am not at all happy about it. Perhaps other people might like to try this code on their systems, and see if it works as intended for them?
>> 
>> http://quality.livecode.com/show_bug.cgi?id=17795
>> 
> 
> 
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