if 'a' is a type, is a*a*a valid? if so, how is calculation order?

invalid. a and b must be variables when we are dealing with '*'. So when we dealing a*a, we found a is a type but not a variable.

oh sorry "we should work from left to right"

oh, sorry. Please forget

calculation order is left to right.

there's no definition for type * type，so it's invaild. if a is a variable,then it is valid, and calculated like:((a*a)*a)(barcket first)