Reference Basic in Perl

Making References

References can be created in several ways.

By using the backslash operator on a variable, subroutine, or value. (This works much like the & (address-of) operator in C.) This typically creates another reference to a variable, because there's already a reference to the variable in the symbol table. But the symbol table reference might go away, and you'll still have the reference that the backslash returned. Here are some examples:

 
   

  
    
 $scalarref = \$foo;
  
    
 $arrayref = \@ARGV;
  
    
 $hashref = \%ENV;
  
    
 $coderef = \&handler;
  
    
 $globref = \*foo;
 
   

Using References

That's it for creating references. By now you're probably dying to
know how to use references to get back to your long-lost data. There
are several basic methods.

1. Anywhere you'd put an identifier (or chain of identifiers) as part of a
   

   variable or subroutine name, you can replace the identifier with a
   BLOCK returning a reference of the correct type. In other words, the
   previous examples could be written like this:
   

      
        
   
       
         
    $bar = ${$scalarref};
       
         
    push(@{$arrayref}, $filename);
       
         
    ${$arrayref}[0] = "January";
       
         
    ${$hashref}{"KEY"} = "VALUE";
       
         
    &{$coderef}(1,2,3);
       
         
    $globref->print("output\n"); # iff IO::Handle is loaded