c:\@Work\Perl>perl -wMstrict -le
"my $expr = '(!(C)&T)&!Q';
 my %allowed = qw{ ( ( ) ) ! !! & &&  C 1  T 1  Q 1 };
 my $finalExpr = map { $allowed{$_} || die qq{not allowed '$_'} } split '', $expr;
 print qq{'$finalExpr'};
"
'11'