-use constant NONE => 0;
-use constant INFO => 1;
-use constant DEBUG1 => 2;
-use constant DEBUG2 => 4;
-use constant QUERY => 8;
-use constant TRACE => 16;
-use constant BACKTRACE_ON_ERROR => 32;
-use constant ALL => 63;
+use constant NONE => 0;
+use constant INFO => 1;
+use constant DEBUG1 => 1 << 1;
+use constant DEBUG2 => 1 << 2;
+use constant QUERY => 1 << 3;
+use constant TRACE => 1 << 4;
+use constant BACKTRACE_ON_ERROR => 1 << 5;
+use constant ALL => (1 << 6) - 1;
+use constant DEVEL => INFO | QUERY | TRACE | BACKTRACE_ON_ERROR;