CODEWITHSUNDEEP
variablesprolog
SwordW
SwordW

Reputation: 610

How to use index to mark unbound variable in prolog?

how can I mark all the unbound variable to number? For example : 

exists(_G1234...all(_G2345...

changes to

exists(1 ... all(2...

("..."menas code which not important)

(exists and all are compound type)

Upvotes: 2

Views: 487

Answers (1)

gusbro
gusbro

Reputation: 22585

I would use term_variables/2 to get the unbound variables and then number them.

index_mark_unbound(Term):-
  term_variables(Term, Vars),
  range(Vars, 1).

range([], _).
range([Value|Vars], Value):-
  succ(Value, NValue),
  range(Vars, NValue).

Test:

 ?- Term=exists(A,all(_,B),A), index_mark_unbound(Term).
Term = exists(1, all(2, 3), 1),
A = 1,
B = 3

Upvotes: 1

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