从文件读取到数据库序言

Question

Hello everyone

I have problem with part of my project for studies. My task is to write a program in prolog that can tell you what illnes do you have based on input from user. Data base must be read from a file which format is up to me.

Construction:

I decide to have 2 dynamic rules;

:- dynamic (illness/2).
:- dynamic (symptoms/4).

where:

illnes(name_of_illness, symptoms(symptom1, symptom2, symptom3, symptom4)

File: example.txt:

flu,cough,fever,head_acke, runny_nose.
measles, rash, fever, sore_throat, inflamed_eyes.

Problem:

My major problem is to format this data to use asserta predicat, I tried many ways but it didn't work.

Thank you

Answer 1

So, per your other question , I think you can parse these strings with split_string/4 , your problem is that the result of that is not atoms, and then you need to build the structure properly. This I think is the piece you're missing:

?- split_string("this,that,the,other,thing", ",", " ", X), 
   maplist(atom_string, [Condition,Sym1,Sym2,Sym3,Sym4], X), 
   Result = illness(Condition, symptoms(Sym1,Sym2,Sym3,Sym4)).
X = ["this", "that", "the", "other", "thing"],
Condition = this,
Sym1 = that,
Sym2 = the,
Sym3 = other,
Sym4 = thing,
Result = illness(this, symptoms(that, the, other, thing)).

If you then simply asserta(Result) you have added the right thing to the database.

If you have a variable number of symptoms, you should keep it a list in there instead, and that would simplify your processing greatly (and probably our downstream code, as doing anything four times in a row is a bit repetitive):

?- split_string("this,that,the,other,thing", ",", " ", X), 
   maplist(atom_string, [Condition|Symptoms], X), 
   Result = illness(Condition, symptoms(Symptoms)).
X = ["this", "that", "the", "other", "thing"],
Condition = this,
Symptoms = [that, the, other, thing],
Result = illness(this, symptoms([that, the, other, thing])).