#!/usr/bin/perl

use warnings;
use strict;
use Switch;

switch ($val) {

   case 1          { print "number 1" }
   case "a"        { print "string a" }
   case [1..10,42] { print "number in list" }
   case (@array)   { print "number in list" }
   case /\w+/      { print "pattern" }
   case qr/\w+/    { print "pattern" }
   case (%hash)    { print "entry in hash" }
   case (\%hash)   { print "entry in hash" }
   case (\&sub)    { print "arg to subroutine" }
   else            { print "previous case not true" }

} # switch

#!/usr/bin/perl

use warnings;
use strict;

# Altvernative mit eval
# ~~~~~~~~~~~~~~~~~~~~~

my $key = 1;

my %switch = ( 1 => "f1('Hallo')",
                2 => "f2",
                3 => "f3",
);

print eval $switch{$key};

sub f1 {
   shift, "\n";
}

sub f2 {
   print "f2\n";
   return;
}

sub f3 {
   print "f3\n";
   return;
}

# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

# 1. Alternative ohne eval
# ~~~~~~~~~~~~~~~~~~~~~~~~

%switch = ( 1 => x1(1,3),
             2 => x2(2,3),
             3 => x3(3,3)
);

my $key1 = 1;

print $switch{$key1}."\n";

# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

# 2. Alternative ohne eval
# ~~~~~~~~~~~~~~~~~~~~~~~~

my $key2 = 2;

SWITCH:{
   if ($key2 == 1) { print x1($key2,10), "\n"; last SWITCH;}
   if ($key2 == 2) { print x2($key2,10), "\n"; last SWITCH;}
   if ($key2 == 3) { print x3($key2,10), "\n"; last SWITCH;}
}


sub x1 {
   $_[0] * $_[1];
}

sub x2 {
   $_[0] * $_[1];
}

sub x3 {
   $_[0] * $_[1];
}

my %switch = ( 
  1 => \&function1,
  2 => \&function2,
  4 => \&function3,
  default => \&irgendwas,
);

my $key = 1;
if ($key and exists $switch{$key}) {
  $switch{$key}->($params); # erst jetzt wird es ausgefuehrt
}
else { # default, wenn noetig
  $switch{'default'}->($params);
}