sub recurse {
  my $level = shift;
  print "recurse [$level]\n";
  recurse($level - 1) if $level > 0;
}

##</code><code>##

#!/usr/bin/perl -w

use strict;

local $\ = "\n";

sub oldsub {
  my $level = shift;
  print "oldsub [$level]";
  oldsub($level - 1) if $level > 0;
}

sub newsub {
  print "newsub [$_[0]]";
}

my $oldsub_ref = \&oldsub;

$oldsub_ref->(2);
print '-' x 10;

*oldsub = \&newsub;

$oldsub_ref->(2);

##</code><code>##

oldsub [2]
oldsub [1]
oldsub [0]
----------
Subroutine main::oldsub redefined at ./typeglob_clobber.pl line 22.
oldsub [2]
newsub [1]

##</code><code>##

my $coderef = do {
  my $selfref;
  $selfref = sub {
    # use $selfref here for recursion
  };
};

##</code><code>##

{
  my $selfref;
  sub named {
    # use $selfref here
  }
  $selfref = \&named;
}