When logging the severity level should convey a certain insight
that the developer has about the code. This can be done with a 3
bit field. These are: known-cause, known-effect and breaks-flow.
This creates the following matrix:
KC KE BF Severity
=================
1 1 0 Trace
0 1 0 Info
1 0 0 Notice
0 0 0 Warning
1 1 1 Error
0 1 1 Critical
1 0 1 Severe
0 0 1 Fatal
A known cause is when the developer knows why a log event is
made. e.g.: if you cannot open a file, you do not know why.
A known effect is when he/she knows what happens after.
Basically, you can tell if it is a catch-all by this flag.
When a severity should only be handled by a debugger, the normal
debug statement should be used. This is in essence a 4th bit.
I hope this helpful in the search for a good level system.