Integer comparison does not behave as expected.

[Edward Gaere]

Arithmetic operator "less-than-or-equal-to" (<=) seems to perform a string comparison rather than a numerical comparison.

I am still a beginner at ProLog/ProbLog. Either way, I thinks it's misleading.

%less than or equal to 12
lte_12(X) :- X @=< 12.

query(lte_12(11)) .
query(lte_12(12)) .
query(lte_12(13)) .
query(lte_12(99) ) .
query(lte_12(100)) .

Output:

lte_12(11):	1
lte_12(12):	1
lte_12(13):	0
lte_12(99):	0
lte_12(100):	1    <-- ??
lte_12(1000):	1    <-- ??

Python 3.8.3
problog==2.2.2

[Edward Gaere]

Solved it. Use intgr(), on both sides, to force a numerical comparison.

lte_12(X) :- intgr(X) @=< intgr(12) .