Type-safe Datalog in OCaml

github.com

80 pointsjlturner4 comments

Very cool.

If you haven't tried it implementing datalog is fun!

Is the implementation any good? Anyone knows a good implementation in any language?

Author here. The implementation is quite straightforward (both for the bottom-up seminaive fixpoint, and for the top-down full prolog with tabling). Good generalist in-memory implementations would be, afaik, [XSB Prolog](http://xsb.sourceforge.net/) (by Warren & al., a full prolog with crazy tabling) and [Z3's fixpoint engine](http://rise4fun.com/z3/tutorialcontent/fixedpoints). The point of this (slightly old) OCaml lib is to have an embedded engine, something I needed a few years ago during my PhD.

There's also RDFox[0] and VLog[1], both of which are implemented in C++.

[0] https://www.cs.ox.ac.uk/isg/tools/RDFox/

[1] https://github.com/jrbn/vlog

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