use Devel::Peek;
my $value = "four";
my @array = ( "one" );
warn "(1):\n" ; Dump($value);

foreach $value (@array)
{
    warn "(2):\n" ; Dump($value);
    print "foreach value: $value\t";
    function();
    sub function {
        warn "(3):\n" ; Dump($value);
        print "function value: $value\n";
    }
}

__END__
(1):
SV = PV(0x8b83b00) at 0x8b83768
  REFCNT = 1
  FLAGS = (PADBUSY,PADMY,POK,pPOK)
  PV = 0x8b992c8 "four"\0
  CUR = 4
  LEN = 8
(2):
SV = PV(0x8b83c20) at 0x8b82c28
  REFCNT = 2
  FLAGS = (POK,pPOK)
  PV = 0x8b962c0 "one"\0
  CUR = 3
  LEN = 4
(3):
SV = NULL(0x0) at 0x8b837b0
  REFCNT = 2
  FLAGS = (PADBUSY,PADMY)
foreach value: one      function value: 

##</code><code>##

use Devel::Peek;
my $value = "four";
warn "(1):\n" ; Dump($value);
{
    $value = "five";
    warn "(2):\n" ; Dump($value);
}
__END__
(1):
SV = PV(0x8bcdb00) at 0x8bcd75c
  REFCNT = 1
  FLAGS = (PADBUSY,PADMY,POK,pPOK)
  PV = 0x8bee7d0 "four"\0
  CUR = 4
  LEN = 8
(2):
SV = PV(0x8bcdb00) at 0x8bcd75c
  REFCNT = 1
  FLAGS = (PADBUSY,PADMY,POK,pPOK)
  PV = 0x8bee7d0 "five"\0
  CUR = 4
  LEN = 8