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Thanks for sharing. There is one very significant conceptual error early on, however, and it is captured first in this statement: "The :- means if and only if, or iff". `:-` means if - or more precisely represents material conditional - where the consequent is on the left and the antecedent is on the right. iff is logical biconditional.
> The :- means if and only if, or iff. Is it really the case? Human("Socrates"). Animal("Turtle"). Mortal(x) :- Human(x). Mortal(x) :- Animal(x). Suppose :- means iff. Turtle is Mortal (lines 2+4, implication to the left). Because Turtle is Mortal, it must be a Human (line 3, implication to the right). Is it really valid according to Datalog semantics?
No, you and sdbrady who commented above are correct; the :- only means "if". I have edited accordingly and apologise for the misunderstanding!
I haven't tried datascript, which appears to support negation. Maybe I will try that if/when I revisit this interest someday.
Earlier quoted context omitted.
Transitive closure is the first thing nearly every introduction to datalog (or Prolog, for that matter) will show you. All you had to do was click the link and scroll down: Edge("a", "b"). Edge("b", "c"). Path(x, y) :- Edge(x, y). Path(x, z) :- Path(x, y), Edge(y, z). Symmetric closure, assuming I'm understanding correctly, is also trivial: SymmetricEdge(Left, Right) :- Edge(Left, Right). SymmetricEdge(Left, Right) :…
I was wondering about termination. With finite ground facts that appears not to be an issue. Complexity is another matter.
Can anyone recommend any implementation of Datalog (+ negation) that is not datomic? I haven't tried datascript, which appears to support negation. Maybe I will try that if/when I revisit this interest someday.
Can anyone recommend any implementation of Datalog (+ negation) that is not datomic? I haven't tried datascript, which appears to support negation. Maybe I will try that if/when I revisit this interest someday.
You can give http://www.dlvsystem.com/dlv/ a shot!
Alternatively, if you prefer open-source solutions, check https://abcdatalog.seas.harvard.edu/.
Due to a number of complications on my machine, I used DLV.
Can anyone recommend any implementation of Datalog (+ negation) that is not datomic? I haven't tried datascript, which appears to support negation. Maybe I will try that if/when I revisit this interest someday.
Hi Joel. You can give http://www.dlvsystem.com/dlv/ a shot! Alternatively, if you prefer open-source solutions, check https://abcdatalog.seas.harvard.edu/ . Due to a number of complications on my machine, I used DLV.
TY for the link to abcdatalog though!
Can anyone recommend any implementation of Datalog (+ negation) that is not datomic? I haven't tried datascript, which appears to support negation. Maybe I will try that if/when I revisit this interest someday.
Check out Datahike aswell, if you are interested in a durable datalog database. https://github.com/replikativ/datahike
Thanks for sharing. There is one very significant conceptual error early on, however, and it is captured first in this statement: "The :- means if and only if, or iff". `:-` means if - or more precisely represents material conditional - where the consequent is on the left and the antecedent is on the right. iff is logical biconditional.
Hi Stephen. You are absolutely right, thank you for the feedback! I have edited accordingly.