in reply to Re^4: Scope Issue
in thread Scope Issue

Note that || and // have different effects when the variable being tested is false! // only tests for undefined. || tests for any false value. ||= will replace 0 or '' with the right hand side value where //= will only replace undef with the right hand side value.

//= behaves like:

$var = $defaultValue if ! defined $var;

||= behaves like:

$var = $defaultValue if ! $var;
True laziness is hard work