This repository contains work in progress for embedding the Clingo ASP solver in SWI-Prolog. To use this, you need:

• Clingo. You need clingo version 5, which is available on github:
  • https://github.com/potassco/clingo
• A recent copy of SWI-Prolog (>= 7.3.x):
  • https://www.swi-prolog.org/

After both SWI-Prolog and Clingo are installed, edit the Makefile to suit your installation. See instructions in the file. After that running make should suffice to build the interface. The interface may be tested by running e.g.:

./swipl.sh examples/map_color.pl
?- map_color(Colors).

Finally, the system can be installed as a SWI-Prolog library using make install.

The basic communication is working. Please do not expect the current interface to be stable. Currently, the interface allows for creating a Clingo program from a string or loading one from a file or from a (not yet settled) representation as a Prolog term. The program can be asked for its stable models (if any) on backtracking. A model is represented as a Prolog list of ground atoms in the predicate logic sense. The interface supports Clingo's abilities to deal with external data and a changing world:

• Clingo atoms may refer to a Prolog predicate
• Clingo's support for parameterized grounding is supported
• Clingo externals are supported
• Clingo assumptions are supported

• Inspect and set configuration options
• Clingo will provide access to the AST (Abstract Syntax Tree) which allow for:
  • Specifying Clingo source using Quasi Quotation fragments
  • Pass identifier, string and variable values that are valid Prolog atoms, strings or variables, but invalid in Clingo's syntax.
• More high level interaction.

• The Clingo user guide can be found here
  • https://github.com/potassco/guide/releases
• The Clingo C API is documented here
  • https://potassco.org/clingo/