Additional Considerations

1. Error checking. A current status variable that tracks the type of the previous token is helpful.
   • Previous token was ( or start

   • Previous token was an operator

   • Previous token was an operand

2. Unary operators, such as unary minus. In the proper context, minus can be converted into a different operator that represents unary-minus.

3. Right-associative operators. Shift when the top-of-stack has the same precedence if the operator is right-associative.

4. Type checking and coercion.

5. Function calls. These can be treated like parenthesized subexpressions, keeping track of the number of arguments.

6. Array subscripts. These can be treated like function calls, then modified to perform subscript calculations.