There is a script that can scrape the CSE department of UCSD for courses, their names, number of unites, descriptions, and requirements. get_all_link will create link for each course page depend on input Quarter and CourseID. parsePrereq will take that link and creat list of prerequirest for that course, and list_to_bool will convert that list to boolean expression. prereq_proc will process such expression and output all possible combination of courses needed to take. builddb will build course database and build/2 will build requirement database based course database and input Quarter.

$ swipl -s builddb.pl

This creates a "database" file, db.pl, used by the backend.

####backend predicates:
===for front end use===
#####getPrereq:
getprereq_fact/3: take Course ID, quarter, and third arg will be requirement fact
getprereq_list/3: same as getprereq_fact, it third arg will be all combination of course needed to take
build/2: take Quarter and file name, then create requirment database

for detial explanation and usage, check each inside the file.

======old predicates=====
courses/1 and course_ids/1. courses/1 can be used to get a list of all courses. The result is a list with one element per course. Each element is a term course/5.
requirement_to_list/3: takes Dept and course ID (in atom) and able to get all possible combination of prerequisites of that course (an atom list).
requirement_to_string/3: same as above, output combination in string format.

####Handcodeddb are coded with following data format, with arguments: #####major/2

1. Department name code
2. Department full name

#####course/5

1. Course ID, an atom
2. Course Title, an SWI7-style string
3. Units, a term (see below)
4. Text description, an SWI7-style string
5. Prerequisites, an atom (for now)

#####requirement/3

1. Department/major name code (atom)
2. Course ID (atom)
3. boolean expression of prerequisites, Course ID are in form of id('Dept','#').

Units are represented as one of three terms:

• exactly(Units): a course is worth Units units (an integer)
• from_to(From, To): a course is worth anything from From to To units
• one_of(List): a course is worth one of the integer values in List

The course_ids/1 can be used to get a list of all course IDs.

1. Course ID, an atom

    ['CSE 3', 'CSE 12', ....]. 

The user should decide how to represent these for a human reader.