you can ‘invoke’ alternative bindings on Y this way: Note the parenthesis are required to keep the correct execution control flow. The ;/2 it’s the general or operator. For your restricted use you could as well choice the more idiomatic that on backtracking binds Y to each member of the list. edit I understood with … Read more
Short answer: No. Medium Answer: Can’t really be done, though one could write a program to check the validity of a given proof fairly easily. In the case of propositional logic, the problem of automatically finding a proof is NP-complete (though it is decidable!), and in first order logic there are true theorems for which … Read more
If x > y, then y – x or (y + (~x + 1)) will be negative, hence the high bit will be 1, otherwise it will be 0. But we want x <= y, which is the negation of this. Even better, drop the shift operator and use a bit mask on the high … Read more
With “or”. As the Lua manual clearly states.
You have to use == to compare (or even ===, if you want to compare types). A single = is for assignment.
Change the ands to ors.
It is common for comparison functions to return 0 on “equals”, so that they can also return a negative number for “less than” and a positive number for “greater than”. strcmp() and memcmp() work like this. It is, however, idiomatic for zero to be false and nonzero to be true, because this is how the … Read more