[Canberra-pm] Recursion in Perl

[Kim Holburn]

There's an excellent section on why not to use bare-word filehandles  
in "Perl Best Practises" which explains it but I always forget it and  
do it wrong.

On 2006 May 25, at 12:13 PM, Andrew Pollock wrote:

> On Thu, May 25, 2006 at 12:02:03PM +1000, Jepri wrote:
>> You haven't included any code, so I'm going to have to guess a  
>> little here.
>>
>> If you are using filehandles created with
>>
>> open HANDLE, "<file"
>>
>> then HANDLE is NOT lexical (does not behave like a normal  
>> variable), and
>> further calls to your function will overwrite HANDLE, probably  
>> causing
>> the first one to close.  I'm guessing here because I never use
>> FILEHANDLES due to their scoping issues.
>
> I was using this method.
>
>> If you use the (much better) lexical
>>
>> my $handle; open $handle, "<file"
>>
>> then $handle is lexically scoped and will be automatically closed  
>> when
>> you leave scope.  If you're using this construction then I'd  
>> really need
>> to see some code to help further.
>
> Yeah, this looks (and sounds) better. I actually got around the  
> problem
> (mostly) by loading up an array with all the files I discovered,  
> and then
> after I closed the file, loop over the array and call the recursive
> subroutine, so the file wasn't kept open as it recursed.
>
> regards
>
> Andrew
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