use Sub::Lexical;

my sub foo {
    print "I'm in a lexically scoped sub, hurrah!\n";
}

foo();

##</code><code>##

local $Sub::Lexical::LEXICALS{foo};
$Sub::Lexical::LEXICALS{foo} = sub  {
    print "I'm in a lexically scoped sub, hurrah!\n";
};

$Sub::Lexical::LEXICALS{foo}->();