[chuck-users] Inner loop array index bug

Stefan Blixt stefan.blixt at gmail.com
Wed Apr 22 15:01:45 EDT 2009


Compilers can't always be expected to understand every kind of error, and
that error message isn't the worst I've seen :) Still, if the opportunity os
there to change it to something better, now harm done. The situation can be
translated to this:
int x;
1 => x[1];

which gives the same subscript error message. Hans's code is otherwise
without problems - ChucK allows (like many other languages) to reuse a
variable identifier in a new block, so x can be redeclared as an int in the
inner while loop, overshadowing the outer x which is an array.

/Stefan

On Wed, Apr 22, 2009 at 5:55 PM, Hans Aberg <haberg at math.su.se> wrote:

> On 22 Apr 2009, at 17:17, Kassen wrote:
>
>  I think ChucK can get pretty confused about this line:
>>>
>>> x[msg.which] => int x;
>>>
>>> ...in which x is treated both as an array and as a newly declared integer
>>> variable. I would rename the array to avoid confusion.
>>>
>> ... I do think ChucK could come up with a better complaint
>> than this;
>>
>> [unnamed1]:line(20): array subscripts (1) exceeds defined dimension (0)
>>
>> With this test code it goes right;
>>
>> int x[2];
>> int x;
>>
>> And we get a rather appropriate
>>
>> [unnamed1]:line(2): 'x' has already been defined in the same scope...
>>
>
> The problem is really that if I remove the second line of:
>   x[msg.which] => int x;
>   x[msg.which] => int x0;
> then the first
>   x[msg.which] => int x;
> is accepted.
>
> So when I add the second line, I get a confusing error message about that,
> not about the first one, which seemed a legal name overload (though
> differing from C++).
>
>  Hans
>
>
>
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