CODEWITHSUNDEEP
prolog
Aontis
Aontis

Reputation: 3

Counting argument values

I'm a beginner Prolog/SWI Owl programmer and would like to calculate the score of words entered in SWI Owl by counting the points that each letter of the word has - just like scrabble!

The points for each word would be stated in the form of facts, like these:

letter_point(a, 1).
letter_point(b, 3).
letter_point(c, 3).
letter_point(d, 2).
%  etc.

The numerical arguments of these facts should be counted using the predicate 'scrabble_score/2' with the word (list) and total score (number) as arguments, in order to get the following result:

?- letters_score([a, b, c, d], Score).
Score = 9.

I'm assuming this could be done with 'is/2' to count the numerical arguments of each letter in the list, but I cannot figure out yet how to get there. Any help as to how to do this would be highly appreciated!

Best, Lara

Upvotes: 0

Views: 167

Answers (1)

Ans Piter
Ans Piter

Reputation: 573

easy solution 

% foo(Arg1,Arg2)

foo(a,1).
foo(b,2). 
foo(c,3).

sum_foo_from_list([],0).
sum_foo_from_list([Arg1|Rest],Sum_Arg2) :-
        % ?Arg2
        foo(Arg1,Arg2), 
        % #= (clpfd library)
        Sum_Arg2 #= Arg2 + Sum_Arg2_,
        % Sum_Arg2 is diffrent to Sum_Arg2_ 
        sum_foo_from_list(Rest,Sum_Arg2_).

test :

| ?- sum_foo_from_list([a,b],N).
N = 3

Upvotes: 1

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