L2R:  ,
R2L:  =  +=  -=  *=  **=  /=  %=  &=  |=  ^=  <<=  >>=
L2R:  ||
L2R:  &&
L2R:  ==  !=  <  <=  >  >=
L2R:  |
L2R:  ^
L2R:  &
L2R:  <<  >>
L2R:  +  - (binary minus)
L2R:  *  /  %
R2L:  !  - (unary minus)
L2R:  ()  []  .

line numbers are precedence values
higher values mean higher precedence