Question

I am seeing both of them used in this script I am trying to debug and the literature is just not clear. Can someone demystify this for me?

Answer 1

Dynamic Scoping. It is a neat concept. Many people don’t use it, or understand it.

Basically think of my as creating and anchoring a variable to one block of {}, A.K.A. scope.

my $foo if (true); # $foo lives and dies within the if statement. 

So a my variable is what you are used to. whereas with dynamic scoping $var can be declared anywhere and used anywhere. So with local you basically suspend the use of that global variable, and use a ‘local value’ to work with it. So local creates a temporary scope for a temporary variable.

$var = 4; print $var, '\n'; &hello; print $var, '\n';  # subroutines sub hello {      local $var = 10;      print $var, '\n';      &gogo; # calling subroutine gogo      print $var, '\n'; } sub gogo {      $var ++; } 

This should print:

4 10 11 4