Just to rephrase this a little. Scalar variables are containers that hold a value. When you assign to a scalar you throw away the value previously contained and overwrite it with a new value.

References are a scalar value that point at (or refer to) other containers. This should be distinguished from an alias which is just a different textual name for the same container. For instance if you modify the first sub: 

sub foo {
  for my $ref ($_[0]) {
    $ref = { all => new };
  }
}
my $hash={};
print $hash,"\n";
foo($hash);
print $hash,"\n";

[download]

$ref is now an alias to $_[0] which is itself automagically an alias to whatever scalar was passed into the subroutine which in this case is the scalar $hash. In this case assigning to $ref inside of the sub is the same as assigning to $hash outside of the sub.

On rereading this it may just cause more confusion, if so I apologise.

---
$world=~s/war/peace/g

In reply to Re: Modifying values by reference: what works and what doesn't by demerphq
in thread Modifying values by reference: what works and what doesn't by markjugg

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