Théo Laurent (Jul 19 2022 at 14:43): Théo Laurent (Jul 19 2022 at 14:43):Hi, I am fairly new to elpi, I hope this in the right place to ask newbie questions.
What's the meaning of the error message "Evaluation of a non closed term (maybe delay)"?
Enrico Tassi (Jul 19 2022 at 14:45):Hello, the place is absolutely right.
Enrico Tassi (Jul 19 2022 at 14:46):This program raises that error
main :- X is A + 1.
indeed A has no value
Enrico Tassi (Jul 19 2022 at 14:47):The maybe delay part is because X is A + 1, A = 0 could still work if one suspends the first part until the second executes
Théo Laurent (Jul 19 2022 at 14:50):Ok.. I don't think I see what I am doing wrong.
So I defined a predicate
pred p i:int.
p K :- K > 0.
and I would like elpi to find me such a K when I do p K, coq.say K
Enrico Tassi (Jul 19 2022 at 19:23):Well, > is a builtin which does not "generate", it only tests.
Also note that you defined p taking the argument in input (it plays no role here, but is fishy).
What are you trying to do actually, the big picture.
Théo Laurent (Jul 20 2022 at 06:04):I was trying to figure out how to write a sudoku solver.
Enrico Tassi (Jul 20 2022 at 07:16):so, elpi is not a constraint solver. your integers are a finite domain, so I see why it made sense.
you can still write something like
pred p o:int.
p 1.
p 2.
p 3.
... etc ....
main :- p K, coq.say "pick" K, K < 3, K >1, coq.say "result" K.
and there elpi will try with any of these, when you ask p K.
Last updated: Oct 13 2024 at 01:02 UTC