my $esc_char = get_escape_case("S");

##</code><code>##

my $case_formatted_string = $esc_char ."FoobAr";

##</code><code>##

use strict;

# determine case of a character
# and return appropriate 'control' code.
sub get_escape_case
{
    my ($char) = @_;
    if ($char eq "\U$char") {
       return '\U'; 
    } else {
       return '\L';
    }
}

# this wouldn't work...
print get_escape_case("S")."stuff\n";

# while this works..
print "\Ustuff\n";