[Chicago-talk] Sharing my pain

Jonathan Rockway jon at jrock.us
Sat Oct 14 23:35:23 PDT 2006

> strict/warnings won't help you; the $sp inside the foreach is *not* the
> 'my'-ed $sp from the line before.  It gets silently localized w/i the

The real subtlety is that $sp is actually the list element that you're 
iterating over: 

@foo = (1, 2, 3);
print "@foo"; # 1 2 3
foreach my $sp (@foo){
print "@foo"; # 2 3 4

The same caveat applies to map and grep, of course.  Don't let the "my" trick 
you into thinking you made a copy, like you do here:

my $a = 0;
print "$a\n";

sub foo {
  my $bar = shift;     #
  $bar++;                 # try $_[0]++ instead

(To achieve that in a for loop, do C<do {my $element = $_; ... } foreach 
@elements> or something similar.)

Jonathan Rockway

package JAPH;use Catalyst qw/-Debug/;($;=JAPH)->config(name => do {
$,.=reverse qw[Jonathan tsu rehton lre rekca Rockway][$_].[split //,
";$;"]->[$_].q; ;for 1..4;$,=~s;^.;;;$,});$;->setup;
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