sub Dump {
    no strict 'refs';
    my $implementation = __PACKAGE__->implementation;
    my $debug; # My own debug variable
    for my $option (@dump_options) {
        my $var = "$implementation\::$option";
        $debug = $var if $var =~/UseCode/; #the option I wish to set
        my $value = $$var;
        local $$var; # <-- PROBLEM! Local to "for", not "sub"
        $$var = defined $value ? $value : ${"YAML::$option"};
        # Here I print out the option in each iteration of the loop
        print STDERR "$debug = $$debug\n";
    }
    # And the final value:
    print STDERR "FINAL: $debug = $$debug\n";
    return &{"$implementation\::Dump"}(@_);
}

##</code><code>##

#!/usr/bin/perl
use strict;
use warnings;
use YAML::Any;

local $YAML::UseCode=1;

my $input = sub {
    print "Enter a value: ";
    return chomp (my $ret = <>);
};

print Dump $input;

__END__
Name "YAML::UseCode" used only once: possible typo at test.pl line 7.
YAML::XS::UseCode = 1
YAML::XS::UseCode = 
YAML::XS::UseCode = 
YAML::XS::UseCode = 
YAML::XS::UseCode = 
YAML::XS::UseCode = 
YAML::XS::UseCode = 
YAML::XS::UseCode = 
YAML::XS::UseCode = 
YAML::XS::UseCode = 
YAML::XS::UseCode = 
YAML::XS::UseCode = 
YAML::XS::UseCode = 
YAML::XS::UseCode = 
YAML::XS::UseCode = 
FINAL: YAML::XS::UseCode = 
--- !!perl/code '{ "DUMMY" }'

##</code><code>##

#!/usr/bin/perl
use warnings;
use YAML::Any;

local ${YAML::Any->implementation()."::UseCode"}=1;
# can't use strict before this because of refs
use strict;


##</code><code>##

@_=qw;
Just another Perl hacker,;
;$_=q=print
"@_"= and eval;