Engine for logic programming hosted in Go.

Logic programming is a paradigm well suited to solving combinatory and constrained problems, where we can express a set of relationships and query the solver for a solution that satisfies all constraints simultaneously.

This library was born as a simple unification solver that eventually grew too big and warranted its own project. It is not intended as a standalone language, but rather a hosted one that is able to manipulate Go objects and call Go code. As such, it may be used as an engine instead of shelling out to a full Prolog environment, which necessarily involve some ser-/deserialization.

• Last-call optimization
• Dicts
• Prolog parser
• DCGs
• Attributed variables
• Packages
• Go integration
• Delimited continuations
• Tabling
• Finite-domain constraint solver

Lots of work ahead :)

The execution environment is an interpreter of the Warren Abstract Machine (WAM), that use regular Go pointers instead of managing memory regions directly (heap, stack, choicepoints). This way, we get garbage collection for free and simplify many other concepts -- for example, we keep separate stacks for environments and choicepoints, and environments that are still referenced won't get lost after they return. We also don't need instructions like put_unsafe_value, that promote a value from the register to the stack, since there's no heap region.

To learn more about the WAM, see Aït-Kaci's tutorial.