Clolog

https://github.com/bobschrag/clolog

by todsacerdoti • 1 year ago

258 41 1 year ago

github.com

mark_l_watson• 1 year ago

Very cool! I just cloned the repository, will play with it later.

BTW, Clojure was such a brilliant name (from Rich): Whenever I see a project starting with "Clo" I pay attention.

EDIT: had a chance to try it: a very cool resource!

iLemming7• 1 year ago

Clojure was such a brilliant name

IIRC Rich wanted a name that has CLR and J in it - Clojure initially was officially to be supported on both .Net and Java stacks. Later he realized that keeping it completely compatible on both platforms is an uphill battle. CLR Clojure still exists, but it's not "an officially supported" runtime.

mappu• 1 year ago

My /usr/share/dict/words offers Clojure, cajolery, and jocular[ly/ity]. Jocular's not bad.

mindcrime2• 1 year ago

Whenever I see a project starting with "Clo" I pay attention.

You're going to love my "Cobol in Clojure" project "Clobol" then!

phlakaton• 1 year ago

"Surely this is a joke," I thought as I read this.

Then I did a Google search just to make sure...

anonzzzies• 1 year ago

This is very nice, I played with it before and working on a similar idea in CL (I am one of those people who finds the uniformity of no syntax soothing).

sterlind2• 1 year ago

really happy to see something of a revival of interest for logic programming lately. it's an extremely powerful tool if you know when to reach for it.

MarkMarine• 1 year ago

When would you reach for it?

winwang2• 1 year ago

I've seen shops (e.g. Netflix I think) use Datalog for certain query types.

iLemming7• 1 year ago

Scheduling, e.g., course scheduling - allocating rooms, professors, time slots while satisfying constraints; Product configuration systems - helping customers select compatible options for complex products; Genealogical research - querying family relationships and ancestry; Static analysis tools for code - finding bugs or verifying properties without execution; Medical diagnosis systems - inferring conditions from symptoms based on medical knowledge; Travel planning - finding optimal routes with multiple constraints; Legal reasoning systems - determining applicability of laws to specific cases; Natural language interfaces - parsing questions and generating appropriate database queries; Hardware verification - proving correctness of circuit designs; Puzzle solvers - Sudoku, crosswords, logic puzzles;

Basically anything that excels when declarative specification of relationships is more natural than imperative algorithms.

baq• 1 year ago

Same reason you’d reach for SQL when querying relations - a good enough tool designed for the job.

The problem has always been getting facts into the prolog system. I’ve been looking for a prolog which is as easy to embed in eg Python or node as a Postgres client and… crickets.

paddy_m• 1 year ago

I'm working on a problem that I think logic programming might be a fit for. And I already have a lisp. Anyone interested in giving me some feedback on a mini language for heuristics?

https://marimo.io/p/@paddy-mullen/notebook-b79pj7

winwang2• 1 year ago

This might unironically be a reason for me to finally try Clojure!

jdminhbg2• 1 year ago

Can anybody comment on when or why to choose this over core.logic?

drob5183• 1 year ago

Clolog is more of a direct translation of Prolog into Clojure, with an s-expression syntax rather than Prolog’s standard syntax, but close. Core.logic is a translation of Mini-Kanren into Clojure and doesn’t use anything close to Prolog’s syntax, even one based on s-expressions. Prolog and Mini-Kanren, while both logic programming systems also use different search algorithms. Prolog uses a depth-first exploration of the solution space, whereas Mini-Kanren uses a breadth-first search. Consequently, Prolog can be more memory efficient (remember, it was created in the 1970s), but it can get stuck in infinite parts of the solution tree and never find a solution. Mini-Karen is less memory efficient as it explores the solution tree more broadly, but it can find solutions even if the solution tree has infinite branches.

So, why/when to choose this? When you want something much more Prolog-like, using the same search algorithm as Prolog. That said, they both do logic programming. I haven’t benchmarked, but from comments in the README, I suspect core.logic will be more performant as it compiles down to Clojure function calls which are then compiled down to Java function calls. It’s sort of like choosing between Python and Java. They both do imperative programming with objects but they both have their own strengths and weaknesses.

jdminhbg2• 1 year ago

Thank you, very helpful.

Blackthorn• 1 year ago

core.logic has a lot of limitations you pretty quickly run into, and they languish on their bug tracker for years now because nobody actually works on it.

Pet_Ant2• 1 year ago

Well this repo seems not to have had any commits for a year, so I'm not sure how much better this is:

https://github.com/bobschrag/clolog/commits/main/

Maybe this post will spark some interest and revitalise it a bit?

cpdean• 1 year ago

I absolutely love the aesthetic of a repo having a giant README.md

SOLAR_FIELDS• 1 year ago

I think about docs a lot and the best docs are the ones that are easiest to find. There is few things right in front of you more than README.md

AtlasBarfed• 1 year ago

So is prolog just a big SAT solver?

drob5183• 1 year ago

No, but they share logic as the foundation. A SAT solver merely solves a series of Boolean equations, typically in conjunctive normal form. Prolog has deduction capabilities that go far beyond that, where you can reason over a tree data structure, computing various parts of it according to a set of constraints. A SAT solver is not Turing complete. Prolog is. You could use Prolog to write a SAT solver (though it wouldn’t be very competitive with solvers written in C or other languages).

perdomon• 1 year ago

Coming from Javascript and PHP, this seems completely foreign and alien and I have almost no idea what I'm looking at. Can't wait to try it.

alex-robbins• 1 year ago

It strikes me as too bad that this API is so imperative. You can see a pattern over and over in the README where they have `do` blocks, in which they clear some global state (`initialize-prolog`), then add some assertions back into that global state (via side-effectful API calls), and finally run a query (which is implicitly a query on the state that's been built up). Why not represent the knowledge base as a normal Clojure data structure, rather than as the effect of a sequence of API calls? Then it can be passed in by the caller alongside the query, instead of being stored as mutable state.

This isn't just a style thing, either; there are consequences. REPL-driven development loses a lot of its slickness when some expressions can only be eval'd in a special context.

Also, what am I supposed to do if two different parts of my program want to use Clolog? If I'm using Clolog, and one of my dependencies is using it too, will we end up trashing each other's global state? (The case of external dependencies is just an example. Let's say I have an application that sets up the Clolog state and runs a query. Part of the setup involves calls to other parts of my application. At the time the code was written, those other parts didn't use Clolog, but now they do, and there's a bug, because those other parts are trashing the Clolog state that their caller had set up, before it runs its query.) Of course, you could get around this by adding something like a dynamically bound variable that points to the instance of state to use, but at that point you're jumping through hoops to support a subpar (stateful) paradigm that Clojure developers expect to be free of.

Pet_Ant2• 1 year ago

Submit a PR? If you have an idea how it would look better, submit it. It's nice that they got it to this point as is. Lets make it better.

Clolog

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