On Sun, Jun 6, 2010 at 08:19, Shawn H Corey <shawnhco...@gmail.com> wrote:
> On 10-06-05 03:26 PM, Bryan Harris wrote:
>>
>> [console]
>> $ perl -e 'use warnings; $c=undef; printf("%s", $c->[0]{dog})'
>> Use of uninitialized value in printf at -e line 1.
>> [/console]
>>
>> Anything that can help me here? I wish it'd say:
>>
>> Use of uninitialized value $c->[0]{dog} in printf at -e line 1.
>>
>> ... but it doesn't.
>
> I wish it would say:
>
> Not an ARRAY reference in printf at -e line 1.
snip
But that is not the problem; autovivification will create the references:
perl -MData::Dumper -le '$c->[0]{a}; print Dumper $c'
The problem is that $c->[0]{dog} doesn't have anything in it (i.e. it
is undef). The error message should theoretically be able to find
that the problem is linked to the variable $c like this one does:
perl -we 'my $c; printf "%s", $c'
but the problem with that is it is only indirectly linked with $c and
you could have a situation like
perl -wle '$c={a=>1,b=>2}; print $c->{z}, $c->{b};'
If the warning said the problem was with $c, you wouldn't know which
expresion was undef, and it might lead you to think that the problem
was with $c, not the fact that you used "z" instead of "a" as a key.
You could make the error message mention the hashref, but, since data
structures can be arbitrarily deep, that could get nasty quickly.
--
Chas. Owens
wonkden.net
The most important skill a programmer can have is the ability to read.
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