Clearly we need left-associative and right-associative inverse parentheses. a & )b $ c) @ d would mean ((a & b) $ c) @ d. a & (b $ c( @ d would mean a & (b $

Clearly we need left-associative and right-associative inverse parentheses. a & )b $ c) @ d would mean ((a & b) $ c) @ d. a & (b $ c( @ d would mean a & (b $ (c @ d)). Combining both, a & )b $ c( @ d would mean (a & b) $ (c @ d). ;)