CSC362L01 2004S, Lab 9: Type Checking

Admin:
* Happy April Fools' day
* Missing: 

Overview:
* Goals of today's lab
* Lab

What should/could the type checker check?
* Assigning a real value to an integer (assigning type a to type b)
* Redefinition of a variable (or giving it two different types)
* Both operands to an operator must have the same type
  * And recursively
  * How do we deal with overloaded function or procedure calls? Assume the return type is the same as the operand type?
* (Casting)
* Verify that the operator can be applied to its operands (e.g., + shouldn't be applied to boolean values; mod shouldn't applied to reals)
* Types must be defined (as used in the declarations section)
* Variables must be declared before being used
* Variables must be initialized before being used