$_ = 254;

my $r = qr{ ^                    # regex bound to start of line
            ((?>\d+))            # what to capture, don't backtrack: (?> )
            (??{
                $1<255 && $1>233 # what is looked for
                ? ''             # if yes, let the regex succeed
                : '(?!)'         # if no, let the regex bail
            }) 
          }x;

print "true ($1)" if /$r/;