You want check a variables by its name ? thus try something like this :

sub reality_test {
    my ( $var_name , $min , $max ) = @_;
    eval "print q($var_name is out of range !) if $var_name < $min or 
+$var_name > $max"
} 

reality_test( '$foo' , 10 , 30 );
[download]

But is not really "programmatically correct" =)
__________________
Hope this helps