There would be a procedure to follow in order to add a new teacher. As information is entered into the system on the new teacher it can be checked to be sure it is within the acceptable guidelines for the position of teacher at that school, to be sure a twelve year old with no degree isn t hired to teach. Once the teacher is successfully added into the system, changes can occur to that teacher s variables. Member functions can be set up to assure that nothing is changed that is not allowed within the teacher objects guidelines, such as a teacher trying to change his salary to three times the maximum limit. The Lisp described in this program will be the original Lisp discussed in the textbook, not common lisp which incorporates many aspects of object orientated programming.
Atoms are symbols or numeric literals that represent an element of information.
A simple list is made up of atoms and a list can be made up of atoms and other lists. It is through these lists and Lisp s ability to dynamically create lists that gives the language the ability to model real world situations. Lisp s lists are heterogeneous, meaning they can hold different types of data in each element of the list. To illustrate Lisp s modeling of real-world situations the same elementary school example will be used to show the modeling of entities, relationships, environments, and rules. In lisp an entity is represented as a list, even if the list is a single atom.