sub lc {
    my $string = shift;
    $string =~ tr/ÁÀÇÉÈËÍÌÏÑÓÒÖÚÙÜ/áàçéèëíìïñóòöúùü/;
    CORE::lc($string);
}

sub uc {
    my $string = shift;
    $string =~ tr/áàçéèëíìïñóòöúùü/ÁÀÇÉÈËÍÌÏÑÓÒÖÚÙÜ/;
    CORE::uc($string);
}