Barliman is written in miniKanren[0], a logic/relational programming system built by Daniel Friedman[1], Will Byrd[2] & Oleg Kiselyov[3]. There are implementations of miniKanren in languages other than Scheme, one of the prominent being Clojure[4].

To oversimplify, in the miniKanren world programs are written using relational logic, wherein there are "variables" and then certain "relationships" between the variables. That is the program specification. Now we can run the specification and allow miniKanren to generate one or more variables that satisfy the relations. Thus a miniKanren program can have more than one answers. One interesting side-effect of this kind of an abstraction is that programs can also be run backwards to generate more programs that satisfy certain relations. That's pretty much what's happening with Barliman.

[0] http://minikanren.org/ [1] https://en.wikipedia.org/wiki/Daniel_P._Friedman [2] http://webyrd.net/ [3] http://okmij.org/ftp/ [4] https://github.com/clojure/core.logic

Some of you might recognize Daniel Friedman as the author of The Little Schemer. If you liked that book, you might check out The Reasoned Schemer. Short, accessible, and a bit mindbending, it offers a compelling introduction to logic programming that culminates in the "invention" of a Prolog-like DSL from basic Scheme primitives. Terrific little book. https://mitpress.mit.edu/books/reasoned-schemer

The induction of logic programs in Prolog from examples was done by Ehud Shapiro's "Model Inference System" described in his PhD thesis, "Algorithmic Programming Debugging" (https://www.amazon.com/Algorithmic-Program-Debugging-Disting...), in 1982.

This was one of the earliest inductive logic programming (https://en.wikipedia.org/wiki/Inductive_logic_programming) systems.

ILP + IFP are nice subjects to read about for this kind of thing. At university a number of people believed ILP and/or neural networks and/or genetic programming would replace programmers shortly. That didn't happen (this was around 25 years ago) but it's still interesting material great to learn from.

You could read "Syntax-Guided Synthesis" by ALUR and al. There is here (http://resources.mpi-inf.mpg.de/departments/rg1/conferences/...) a presentation he did at a summer school last summer.

Second that. This looks brilliant. Had no idea something like this existed :)