HOW TO DO IT

The first step was to define all the chapters that are going to be covered by the tutorial. Those topicse are:

An introduction
data structures
Basic operations
sets
Basic input/output
Control Structure
Mathematical operations.

Also within of each topic, subtopics related to the main topic may be expanded. For example in the data structure topic the subtopics are Atoms and S-expressions. In the set Topic the subtopics are member, union, intersection, adjoin, and so on for each topic.

Additionally, each subtopic has to be explained with its definition, examples about it, some exercises provided for the student and some feedback for that exercise.

The implementation of the exercise is based on the FORM clause of the hypertext Markup language and The CGI (Common Gateway Interface) of a Web Server allows a browser's request to run a program written in a language such as C or PERL, or even a Unix shell script. In this implementation the exercise text typed by the user is going to be stored in an environment memory that can be accessed by any program, written in C or a script language executed with the POSTACTION feature of this FORM clause.

The external programs that the tutorial has are:

A C program, called atom-checker, that takes the text of the atoms that the user typed and returns a hypertext with the result and its explanation.
A program, called run-gcl, that receives a text and executes the Lisp interpreter with that text and formats the output produced by the compiler to be presented to the student. It is used when the user has the freedom to write the whole Lisp exercise.
A program, called run-gcl-args, that is similar to the previous ones but instead of a single text, it will receive a text that is going to make the role of template, like:
```
(defun second (l)
  (cond ($1     nil)
        ($2 (caar l))))
```
Where $1 will be associated to the variable 1, $2 to variable 2, and so on. Also receiving the value of all these variables (1, 2, ...). In the example variable 1 can be "(null l)" and variable 2 can be "else", that will be merged into the template before it is passed to the Lisp interpreter, and then the output is formatted to the student.
The last program, called tutor-assistant, is in charge of take the On-line test and grading with a little help from the calculator program of unix (bc). It also saves the results for statistical analysis (in the future).

The next step, when we finished the chapter to be covered, was to join them together, using this graphic teacher board.

It displays all possible topic, with a script map, called lsplogo.map. Here it defines several regions in the graphic and each region is associated with a topic or subtopic, and when the student points and clicks over this region the corresponding topic will be presented.

villamil@eecs.tulane.edu