Prolect

An OCaml Derivation of the Warren Abstract Machine.

Language support is limited to pure Prolog i.e. predicate logic with Horn clauses.

This is a very simple & plain Prolog interpreter with no support for negation as failure, integers, lists, operators or built-in predicates.

Implementaion-wise, there is no tabling or memoization nor any type of term indexing. The core part of the interpreter is only ~100 LOC.

Usage

Install using the opam package manager:

opam install prolect

Then run it, potentially with a consulting file:

prolect test.pl

Linux

If you don't want to use opam, download the .exe from GitHub releases, add the executable attribute (chmod +x prolect.exe), and then:

./prolect.exe

Other OSes

If you don't want to use opam, download the .bc from GitHub releases, install the OCaml Runtime, and then:

ocamlrun prolect.bc

Compile it yourself

If you don't want to use the bytecode interpreter either, you can compile the project yourself (e.g. for getting a performance boost on other OSes).

First, install the dependencies (ocaml, dune, etc.). Then:

dune exec prolect --profile release

The exe

To get the executable:

dune build . --profile release

Run the REPL:

_build/default/bin/prolect.exe

Example

Provided that you've given the test consulting file (i.e. running prolect test.pl instead of prolect):

Welcome to Prolect (version 1.1.3)

?- ancestor(terah, jacob).
true .

?- ancestor(terah, X).
X = sarah ;
X = abraham ;
X = isaac ;
X = jacob ;
X = isaac ;
X = ismael ;
X = jacob .

?- loves(sarah, X).
X = isaac ;
X = loves(sarah, isaac) ;
X = loves(sarah, loves(sarah, isaac)) .

?- ^C

Future plans

• Improve error handling
• Add files importing facilities
• Add term indexing