A simple programming language and inference engine powered by backward chaining. When given rules and facts, it will deduce new information.
pip install backward
>>> from backward import Backward
>>> ctx = Backward()
>>> _ = ctx.evaluate("a => b")
>>> _ = ctx.evaluate("b => c")
>>> _ = ctx.evaluate("= a") # a is true
>>> ctx.evaluate("a b c") # are b and c true?
[True, True, True]You can also type python -m backward into your shell to enter an interactive REPL.
C => E # C implies E A & B & C => D # A and B and C implies D A | B => C # A or B implies C A & !B => F # A and not B implies F C | !G => H # C or not G implies H V ^ W => X # V xor W implies X A & B => Y & Z # A and B implies Y and Z = A B G # Initial facts : A, B and G are true. All others are false. G V X # What are G, V and X ?
Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change. Please make sure to update tests as appropriate.