#!/usr/bin/perl -w 

use strict;

sub Case1
{
 print "AtUnderscore: ",(join ",",@_),"\n"; 
 print "shift: ",shift,"\n";

 # string is now gone from @_ , which means
 # that $_[1] should be 5, and $_[2] is undef
 # This shows to be true (see output Case1)

 print "AtUnderscore after shift: @_\n";
 print "\$_[1]: $_[1]\n";
 print "\$_[2]: $_[2]\n";
};

sub Case2
{
 print "AtUnderscore: ",(join ",",@_),"\n"; 

 # Please explain to me HOW I can shift @_
 # here, but still have access to the original
 # $_[2] (see var $Rubbish)...

 my $Rubbish=join "",(split //,shift)[$_[1]..$_[2]];

 # But HERE I lost the access to $_[2]. 
 # its gone!!!

 print "Rubbish: $Rubbish\n";
 print "1: $_[1]\n";
 print "2: $_[2]\n";
};

print "\n\nCase1:\n";
Case1("This_is_a_string",3,5);
print "\n\nCase2:\n";
Case2("This_is_a_string",3,5);

##</code><code>##

Case1:
AtUnderscore: This_is_a_string,3,5
shift: This_is_a_string
AtUnderscore after shift: 3 5
$_[1]: 5
Use of uninitialized value in concatenation (.) at ./mysplit line 16.
$_[2]: 


Case2:
AtUnderscore: This_is_a_string,3,5
Rubbish: s_i
1: 5
Use of uninitialized value in concatenation (.) at ./mysplit line 34.
2: