Cubist's first bug report

dsc at swcp.com dsc at swcp.com
Sun Jun 5 15:15:11 EDT 2016


Here's a script (derived from Mark's) that illustrates the double call:

local sRandomCount

on mouseUp
	put LF into newLine
	put 0 into sRandomCount
	put "0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0" into myVar
	repeat 100
		add 1 to item myrandom(16) of myVar
		put myVar & newLine after myTempList
	end repeat
	put sRandomCount & tab & sum(myVar) & newLine & myTempList
end mouseUp

function myRandom n
	add 1 to sRandomCount
	return random(n)
end myRandom




> On Jun 5, 2016, at 12:42 PM, Dar Scott <dsc at swcp.com> wrote:
> 
> 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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> 
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