SABR (Spatial and Action Based Resolver) is a constraint programming language designed with an emphasis on spatial and temporal logic.

Programs compile to CNF (Conjunctive Normal Form), which is then solved by a CNF solver.

The goal of the language is to make representing operations research problems not just possible, but also intuitive and the solving of these problems efficient.

From a theoretical perspective, the language can also be used to prove a problem is NP-Easy and to verify properties about automata and systems that can be modeled as automata such as circuits and programs.

SABR is installed using setup.py.

Build SABR and the CNF solver:

python setup.py build

For more commands:

python setup.py help

To run SABR, provide an optional flag, the number of stages to use, and the input source path. The solution can be found in result.txt.

Example:

./sabr 20 test/Simple/simple.tb

For more commands:

./sabr --help

Testing can be done with test.py.

Runs all tests:

python test.py all

For more commands:

python test.py help	

Let's see what the traditional river crossing puzzle looks like in SABR. A more detailed walkthrough is also available.

Sym { west east }

# each cell on the board can be any symbol
Board { cabbage goat wolf sailor }
Start { west west west west }
End { east east east east }

# transitions for object Crew
# sailor can take one passenger east or west
Trans SailEast:Crew { west west => east east }
Trans SailWest:Crew { east east => west west }

# describe object Crew's cells
DesObj Goat:Crew { sailor goat }
DesObj Cabbage:Crew { sailor cabbage }
DesObj Wolf:Crew { sailor wolf }
DesObj Alone:Crew { sailor sailor }

# options for object Watch, at least one must match
# sailor needs to be watching these two if they are together
Opt Watch { side side side }
Opt Watch { !side !side side }
Opt Watch { !side side !side }

DesObj Watch { sailor goat cabbage }
DesObj Watch { sailor wolf goat }

Running ./sabr 10 source.tb shows us the answer to the puzzle in result.txt (https://gist.github.com/dbunker/4966217).

For more documentation check /doc/LANGUAGE. Simple python module can be found at /module/sabr.py

Website: http://sabrlang.org
Examples: http://sabrlang.org/river/