Octave does not support the matlab ! command.
However the lexer does not treat the ! differently between octave and matlab.
In addition, octave uses the ! as the NOT operator (as well as ~ like matlab does), but the lexer doesn't support that syntax (it does work for != though)
Patch attached to handle both cases.
Committed as [3c9f76].
Related
Commit: [3c9f76]