#!/usr/bin/env perl
use warnings;
use strict;

sub foo { print "orig foo\n" }
sub bar { print "orig bar\n" }
{
	local *foo = sub { print "local foo\n"; };
	local *bar;
	sub quz {
		foo();
		eval { bar(); 1 } or warn "calling bar failed: $@";
	}
	sub baz {
		*bar = sub { print "local bar\n"; };
	}
	quz();  # first call to quz
	baz();  # first call to baz
	quz();  # second call to quz
}
quz();  # third call to quz
baz();  # second call to baz
quz();  # fourth call to quz

__END__

Subroutine main::foo redefined at local_ex.pl line 8.
local foo
calling bar failed: Undefined subroutine &main::bar called at local_ex.pl line 12.
local foo
local bar
orig foo
orig bar
Subroutine main::bar redefined at local_ex.pl line 15.
orig foo
local bar