Actually the "v = (v + 1) % 2" approach has merit -- in the past I've had to write MHEG textual notation, which is a declarative language where the syntax for

Actually the "v = (v + 1) % 2" approach has merit -- in the past I've had to write MHEG textual notation, which is a declarative language where the syntax for conditionals is phenomenally ugly and ludicrously verbose, and this method is vastly more concise (2 lines versus about 10)