Looking at the example, my immediate reaction was that the main advantage would be the `anything_but` method, relieving me from the cumbersome construction of stuff like this:
(?:[^t]|t(?:[^r]|r(?:[^u]|u(?:[^m]|m[^p]))))
What a time-saver it would be to write
anything_but("trump")
Except, then you look at the source code and see this:
Except not all applications of regular expressions allow for that trick to be used. Case in point: grep (which of course has the -v option which together with pipes does the whole negative match thing much more neatly anyway).
How else would you write that you want to match all strings that don't contain string X? If you were matching at a specific position, you should use a negative lookahead (?!xyz), but I think in some cases you might need the mess above.
If you concede that the standard regex construct [^x] is a useful construct at all -- match any character except x -- why would should such a negative match be restricted to only a single character? Why not also allow for, say, match anything except the following _two_ characters in a row?
Well, then by application of your name, it should be useful for any number of characters. They're not random -- they spell out a word you would like not to match.
I'm not sure what you mean with "predictable". Are you referring to readability of the expression? I totally give you that... which kinda was my whole argument to begin with.
