Interesting behaviour with lexical variable

Hi to all,

while playing with code like this:

use warnings;
while (my $input = <STDIN>){
my $num = abs $input;
print add();

sub add {
$num + $num;
}
}

I found out that once the loop get executed for the second
time, the variable $sum gets "splitted", taking the new value
from $input in the loop, but leaving the old, previous value
in add().

I was wondered a litte bit because I couldn't found described
this behaviour anywhere in the docs.

If, however, the entire code is placed again in another function,
and this function is then called:

use warnings;
sub main {
... # See above, starting with "while..."
}
main();

I get this message:

Variable "$num" will not stay shared at x.pl line 11.

explaining what actually will happen here (although I can't
understand _why_ it does happen - it's the same lexical
variable within the same scope - so why will/can it not
longer stay shared?).

So just for curiosity this question: the same behaviour
occurs twice, but gets reported only once. Is this expected
or perhaps a (small) bug?

BTW: This is perl 5.8.8 (as well as 5.6.1).

Greetings, Ferry

--
Ing Ferry Bolhar
Magistrat der Stadt Wien - MA 14
A-1010 Wien
E-Mail: bol@xxxxxxxxxxxxxxxxx




.

Relevant Pages