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I second the recommendation in Sir Whinesalot's post (which I haven't fully read yet) to look at miniKanren and microKanren. I found it extremely educational to

by kragen 1y ago

I second the recommendation in Sir Whinesalot's post (which I haven't fully read yet) to look at miniKanren and microKanren. I found it extremely educational to port microKanren to OCaml a few years ago, and I think the result is somewhat more comprehensible than the original Scheme, though you'll still probably have to read the paper to understand it: http://canonical.org/~kragen/sw/dev3/mukanren.ml http://canonical.org/~kragen/sw/dev3/mukanren.ml The most astonishing result of miniKanren is a Scheme interpreter that you can run forwards, backwards, or both. http://webyrd.net/quines/quines.pdf http://webyrd.net/quines/quines.pdf demonstrates using it to generate a Scheme quine, that is, a Scheme program whose output when run is itself ("miniKanren, Live and Untagged: Quine Generation via Relational Interpreters (Programming Pearl)", Byrd, Holk, and Friedman). §4.4 of SICP http://sarabander.github.io/sicp/html/4_002e4.xhtml http://sarabander.github.io/sicp/html/4_002e4.xhtml also has an implementation of logic programming in Scheme which is extremely approachable. Unlike the post, I don't think Datalog is the place to look for deep insights about logic programming. Instead, it's the place to look for deep insights about databases.

fcatalan 1y ago
I concur that SICP 4.4 is very approachable. I once took a class that had a simple Prolog assignment, I recall we were given some building plans and had to program a path solver through the building. I thought it was a bit too easy and I wanted to dig deeper, because just doing the task left you with a taste of "this is magic, just use these spells". I looked at how to implement Prolog and was stumped until I found that SICP section. So I ported it to JavaScript and gave it a Prolog-like syntax and made a web page where you could run the assignment but also exposed the inner workings, and it was one of the neatest things I've ever handed in as coursework.
sirwhinesalot 1y ago
Insights shminsights, the database connection is where it is at :P (Thank you for reading the article, I also implemented microKanren before and it's insane how little code it takes to get full a logic programming engine going)
anthk 1y ago
Among SICP, https://t3x.org/amk/index.html https://t3x.org/amk/index.html Same approach. I think an older version of the book it's freely available, or maybe the one on Scheme itself. Scheme being homoiconic makes far easier to create quines.

by kragen 1y ago

fcatalan 1y ago

I concur that SICP 4.4 is very approachable. I once took a class that had a simple Prolog assignment, I recall we were given some building plans and had to program a path solver through the building. I thought it was a bit too easy and I wanted to dig deeper, because just doing the task left you with a taste of "this is magic, just use these spells". I looked at how to implement Prolog and was stumped until I found that SICP section. So I ported it to JavaScript and gave it a Prolog-like syntax and made a web page where you could run the assignment but also exposed the inner workings, and it was one of the neatest things I've ever handed in as coursework.

sirwhinesalot 1y ago

Insights shminsights, the database connection is where it is at :P (Thank you for reading the article, I also implemented microKanren before and it's insane how little code it takes to get full a logic programming engine going)

anthk 1y ago

Among SICP, https://t3x.org/amk/index.html https://t3x.org/amk/index.html Same approach. I think an older version of the book it's freely available, or maybe the one on Scheme itself. Scheme being homoiconic makes far easier to create quines.