The underscore character "_" is no longer considered a word separator. The special case of "_" as the last character is handled separately, but only when not in the context of another words. This means that ending a line with "bob_" will keep "_" as part of the variable rather than colorizing it differently. This also prevents "a_2" from showing the 2 as a number and "_" as a special character.

Perhaps I should not treat "_" as a word separator in other languages either.....