Variables and Assignments

Note that the is equal to "=" operator is different than the assignment operator ":="
- z = x;
- z;
Something such as "z = x" is a boolean expression, it has a value of true or false
- y = x;
evalb evaluates boolean expressions
- evalb(");
- evalb(1 = 2);
a boolean expression can be assigned to a variable
- z := x = y #z := (x=y)
- evalb(z);> x = 'x'; y = 'y'; z = 'z';