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Ask HN: What's Prolog like in 2024?

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Re: Ask HN: What's Prolog like in 2024?

#161

Post by rscho »

strangattractor wrote: post #156
everforward wrote: post #136

Earlier quoted context omitted.

> A few dedicated clever people and idealists and dreamers talking about ontologies and building things I don't understand I was briefly deeply interested in ontologies via OWL and I suspect Prolog has the same issues that I think plague ontologies in general. They are a fantastic tool for a system complex enough to be nearly useless. Modelling an ontology for a reasonably complex domain is unreasonably difficult. No…

I had similar discussions with people that wanted to encode published research into ontologies. I would ask researchers what they think - the answer was always great idea. I would then follow up with - How would you use it? No response. I finally concluded that it would never happen. 1. No one wanted it enough to pay for it to happen. 2. There is always a turn over of ideas coming and going which can never be suffici…

A theorem prover for the medical literature:

https://github.com/webyrd/mediKanren

http://minikanren.org/workshop/2020/minikanren-2020-paper7.p...

Not prolog though. But gives an idea about the goals behind the classification of science papers.

Re: Ask HN: What's Prolog like in 2024?

#162

Post by varjag »

everforward wrote: post #136
jodrellblank wrote: post #116

What is it like? 50 years of historic cruft. Questionable whether there are more trip hazards than usefulness for ordinary coding. A fractured community which feels like there are more Prolog systems than Prolog code. Learning Prolog is less "how do I do things in Prolog" and more "how do I contort my things to avoid tripping over Prolog?". A few dedicated clever people and idealists and dreamers talking about ontolo…

> A few dedicated clever people and idealists and dreamers talking about ontologies and building things I don't understand I was briefly deeply interested in ontologies via OWL and I suspect Prolog has the same issues that I think plague ontologies in general. They are a fantastic tool for a system complex enough to be nearly useless. Modelling an ontology for a reasonably complex domain is unreasonably difficult. No…

This is why Lenat and CYC had settled on micro-theories. They found it impossible to build a useful universal ontology so had to fracture them on domain boundaries.

Re: Ask HN: What's Prolog like in 2024?

#163

Post by Suppafly »

tomstuart wrote: post #4

Definitive reference: https://www.urbanautomaton.com/blog/2015/08/10/the-pledge-to...

>Q: What if Prolog is not suitable for my employer’s problem domain?

>

>Prolog is not suitable for any problem domain, although this is more readily apparent for some domains than others.

At least they are honest about it LOL

Re: Ask HN: What's Prolog like in 2024?

#165

Post by derdi »

ted_dunning wrote: post #131
inkyoto wrote: post #121

Earlier quoted context omitted.

A unique property of Prolog is that, given an answer, it can arrive at the original question (or, a set of questions – speaking more broadly). Or, using layman terms, a Prolog programme can be run backward.

To be precise, a small number of very small Prolog programs can be run backwards. There are essentially no significant Prolog programs that are reversible with acceptable efficiency.

To be even more precise, Prolog programs only ever run forward because the order of evaluation is fixed as top-down, left-to-right. These notions of "forward" and "backward" are very unhelpful and should be given up. Beginners find the order of evaluation hard enough to understand, let's not confuse them even more.

Also, the notion is woefully incomplete. Let's say we consider this "forward":

    ?- list_length([a, b, c], Length).
    Length = 3.
Then you would say that this is "backward":

    ?- list_length(List, 3).
    List = [_A, _B, _C].
Fine, but what's this then? "Inward"?

    ?- list_length([a, b, c], 3).
    true.
And then presumably this is "outward":

    ?- list_length(List, Length).
    List = [], Length = 0 ;
    ...
    List = [a, b, c], Length = 3 .
None of these cases change the order of evaluation. They are all evaluated top-down, left-to-right. The sooner beginning Prolog programmers understand this, the better. The sooner we stop lying to people to market Prolog, the better.

Re: Ask HN: What's Prolog like in 2024?

#166

Post by tashmahalic »

shrimp_emoji wrote: post #41
jeroenvlek wrote: post #38

Earlier quoted context omitted.

What a curious swap. May I ask which course he taught?

It was a whirlwind "survey of languages" course. After blowing our minds with functional programming via OCaml, the last segment was traditionally logical programming via Prolog. But he decided to spare us, I guess, and made me fall in love with Rust for a few years. :p (Or he sadistically meant to inflict the trauma of knowing how much better C and C++ could be but never will be, which stays with you even after you…

I’d love to hear more about your trauma :-). What are the main ways C and C++ could be better?

Re: Ask HN: What's Prolog like in 2024?

#167

Post by forgetfulness »

wk_end wrote: post #150
chamomeal wrote: post #122

Earlier quoted context omitted.

What do you mean by LISP as a siren call? I’ve just started learning clojure and besides the lack of static types (which is pretty harsh for me), it seems like a fun and practical language.

Imagine it's, like, 1980 - or even earlier - and you can work in a language roughly as nice as Clojure, except the rest of the world is stuck working with pre-ANSI C or Pascal or FORTRAN or COBOL or raw assembly language. There's no Python or Java or C# or Ruby or Perl or Haskell or Scala or Kotlin or Rust or JS/TS. Nothing really resembling our modern idea of a high-level language. (OK, there was Smalltalk. Let's ig…

There's also the not all small factor that there was glam to Lisp.

Early Internet discourse around programming was dominated by people who had ties to elite universities in the 1980s, who yearned for the times when the US Government was throwing an abundance of money to the AI industry of the time.

They were the ones rubbing elbows with researchers from MIT, Stanford, Harvard, and Berkeley, who were using specialized hardware and software beyond the capabilities available to that of developers working on more mundane applications, all graciously funded by DARPA initiatives.

That experience was, in truth, unrelatable to young people reading the recollections of ESR and RMS of the period, the in-jokes of these people, their ideas and interactions, but the tales of Lisp, the Lisp hackers and their fabled Lisp machines would be extremely appealing to someone who was very passionate about programming, striving for excellence as a programmer, and to advance in life through merit. Paul Graham would seal the deal with his essays.

Re: Ask HN: What's Prolog like in 2024?

#168

Post by forgetfulness »

slashdave wrote: post #130
jodrellblank wrote: post #116

What is it like? 50 years of historic cruft. Questionable whether there are more trip hazards than usefulness for ordinary coding. A fractured community which feels like there are more Prolog systems than Prolog code. Learning Prolog is less "how do I do things in Prolog" and more "how do I contort my things to avoid tripping over Prolog?". A few dedicated clever people and idealists and dreamers talking about ontolo…

Who still has nightmares of infinitely nested parenthesis?

The more nightmarish thing about Clojure is realizing that, in truth, you have no idea what all these dicts you are passing around the terse, nil-punning functions of your codebase hold at any given time.

Re: Ask HN: What's Prolog like in 2024?

#169

Post by gnulinux »

I recommend that you check Souffle programming language out, here: https://souffle-lang.github.io/index.html

* It is a dialect of Prolog

* It reads from and writes to SQLite database format as well as CSV. This allows you to preprocess or postprocess data Souffle produces, or Souffle reasons. E.g. you can generate bunch of data in Python, output Sqlite, reason in Souffle. Load reasoning output back into python via sqlite.

* It is pretty feature complete when it comes to logical reasoning, and transactional database management. You get best of both Prolog and Sqlite worlds.

Re: Ask HN: What's Prolog like in 2024?

#170

Post by nickswalker »

networked wrote: post #113
mark_l_watson wrote: post #88

Earlier quoted context omitted.

I have two short examples in one of my books that I am currently re-writing. Here is a link directly to the Python+ Prolog interop examples https://leanpub.com/pythonai/read#use-predicate-logic-by-cal...

Thanks for the link. I have played with PySwip ( https://github.com/yuce/pyswip ), and the MQI looks like a more maintainable approach to integrating SWI-Prolog with Python ( https://github.com/SWI-Prolog/packages-mqi ). The biggest source of friction I noticed when playing with PySwip was that because Prolog code was represented as strings, you avoided generating it on the fly. It would be nice to have an embedded D…

I noticed the same friction while trying to integrate Answer Set Programming solvers into Python projects. The people who built the dominant ASP solver actually provide nice solutions though. Possible inspiration for Prolog tooling:

Clorm (Clingo ORM) [1] makes it easy to create facts after you define simple predicate Python classes. Here's an example project of mine which uses it to set up a scheduling problem (Python -> ASP) and to present the results (ASP -> Python).

https://github.com/raceconditionrunning/relay-scheduler

Clingo (the solver) exposes its internal AST implementation through Python bindings[2], so you can build up rules or other statements from typed components instead of strings. This simplifies the translation bits of implementing an ORM or whatever kind of wrapper a developer would prefer.

[1] https://github.com/potassco/clorm [2] https://potassco.org/clingo/python-api/current/clingo/ast.ht...

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