I'd like to point out that these aren't really closures...
The read_row function is a closure, it just happens to be a non-encapsulated closure as process can also see @indexes. It would act as a more effective closure if it was re-structured like so 
use Symbol;
{
  my @indexes = qw (3 0 4 5 6 7);
  my $fh = gensym;
  open $fh,"<my.dat" or die "my.dat: $!";
  sub read_row {
   my $row = <$fh>;
   close $fh and return unless defined($row);
   return (split(/\s+/,$row))[@indexes];
  }
}

[download]

HTH

_________
broquaint

In reply to Re: Re: Closures and callbacks... by broquaint
in thread Closures and callbacks... by rdfield

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