eyelog
eyelog is a C Prolog-style rule engine with an RDF bridge through triple(S, P, O).
It materializes distinct triple/3 consequences by Horn-clause search, with duplicate suppression and guarded recursion for common cyclic closures.
Its inherent potential comes from the small, general Horn-clause core: unification, goal-directed proof search, and triple/3 materialization provide a compact foundation on which RDF reasoning, graph algorithms, transformations, and higher-level rule languages can be built. The theoretical underpinning is deliberately simple and well understood, making eyelog a lightweight logic kernel rather than a large specialized reasoner.
Current version: see VERSION.
Try it in the browser playground.
Quick start
Build the native command-line executable:
make cli
Run examples, queries, multiple inputs, stdin, or a URL:
bin/eyelog examples/delfour.pl
bin/eyelog --query 'triple(pat, ancestor, X)' examples/ancestor.pl
bin/eyelog facts.pl rules.pl
printf 'triple(stdin, works, true).\n' | bin/eyelog -
bin/eyelog https://raw.githubusercontent.com/eyereasoner/eyelog/refs/heads/main/examples/ancestor.pl
The default make / make all builds both the native CLI and browser assets, so it also requires Emscripten’s emcc.
Browser playground
Build and serve the local playground:
make browser
make serve
Then open http://localhost:8000/playground.html.
Read further
Read the language specification for the normative Prolog-like language definition. Read further in the HANDBOOK for examples, browser use, indexing, tests, release workflow, and GitHub Pages deployment.