I thought (maybe too long) on that issue. I decided that, even though it would be silly for a parser (or designed language) to do the wrong thing with sequences of \[+ - ~\], that showing associativity explicitly could help those who might wonder if parentheses were needed. So I did not see it as superfluous. I removed the associativity where it would answer no practical questions. For example, "What does 'NOT NOT \<expression\> mean?' " and "Can I write (and get away with) that?"