An implementation of a novel Prolog virtual machine, proposed by Paul Tarau.

See http://www.cse.unt.edu/~tarau/research/2017/eng.pdf for details.

Ported to Javascript, C++ and Pascal by CapelliC.

Some interesting properties, from the above document abstract:

• the heap representation of terms and the abstract machine instruction encodings are the same
• no dedicated code area is used as the code is placed directly on the heap
• unification and indexing operations are orthogonal
• filtering of matching clauses happens without building new structures on the heap
• variables in function and predicate symbol positions are handled with no performance penalty
• a simple English-like syntax is used as an intermediate representation for clauses and goals
• the same English-like syntax can be used by programmers directly as an alternative to classic Prolog syntax
• solutions of (multiple) logic engines are exposed as answer streams that can be combined through typical functional programming patterns
• performance of a basic interpreter implementing our design is within a factor of 2 of a highly optimized WAM-based system

Ported to plain Javascript, simplifying somewhat the code. Running in Firefox, performance are about 1/3 of Java 8.

Several data structures have been replaced by arrays constructs: IntList, IntStack, IntMap, ObStack

Available to run in browsers or NodeJS.

Ported to C++ from Javascript, with small optimizations. Slightly faster than Java 8.

Most data structures have been replaced by std::vector: IntList, IntStack, IntMap, ObStack

Ported to Free Pascal from C++. Performance still to be evaluated.

Most data structures have been adapted from Generics. The recursive data structure used for term interfacing has been redesigned and a little optimized.