Re^4: my (0?$a:$b): a koan

Nice -- it's a kind of clever inside-out way to say

my $a if 0;
my $b = 3;
[download]

EDIT: As seen with this:

$a=1;
$b=2;
sub x {
    my (0?$a:$b) = shift;
    print"a=$a\nb=$b\n";
    $a=shift
}
x(3,30);
x(4,40);
__END__
# OUTPUT:
a=
b=3
a=30
b=4
[download]

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Re^5: my (0?$a:$b): a koan by wind (Priest) on May 04, 2011 at 21:24 UTC
Ok, now that just confuses the fuck out me. Obviously this is a convoluted use of my and so I shouldn't worry about it too much. But these results don't match the explanation you gave earlier. If the theory is that both $a and $b get assigned a lexical at the beginning of the sub, than $a should be undef every sub call. `$a=1; $b=2; sub x { my (0?$a:$b) = shift; print"a=$a\nb=$b\n"; $a=shift } x(3,30); x(4,40); x(5,50); __END__ #Output a= b=3 a=30 b=4 a=40 b=5` [download]	[reply] [d/l]

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Re^5: my (0?$a:$b): a koan
by wind (Priest) on May 04, 2011 at 21:24 UTC

Ok, now that just confuses the fuck out me.

Obviously this is a convoluted use of my and so I shouldn't worry about it too much. But these results don't match the explanation you gave earlier. If the theory is that both $a and $b get assigned a lexical at the beginning of the sub, than $a should be undef every sub call.

$a=1;
$b=2;
sub x {
    my (0?$a:$b) = shift;
    print"a=$a\nb=$b\n";
    $a=shift
}
x(3,30);
x(4,40);
x(5,50);
__END__
#Output
a=
b=3
a=30
b=4
a=40
b=5
[download]

[reply]
[d/l]