Backward-chaining inference engine in Ruby - 42 school project
ruby expert_system.rb [path/to/file]
or
ruby expert_system.rb => run [path/to/file]
B => A # if B(true) then A(true)
D + E => B # if D and E then A
!G + H => !F # if G(false) and H(true) then F(false)
I + J => G
G <=> H # biconditional rule: if G then H but also if H then G
L | M => K # if A or M ...
L ^ M => K # if A xor M ...
O + P => L | N # ambiguous: L or N are undetermined
N => M
(F | G) + H => E # parentheses handling
=DEIJOP # By default, all facts are false, and can only be made true by this initial facts statement.
?AFKP # list of queries
====================================== COMMANDS =======================================
# #
# run [file path] : load a file and run it. Reset all facts #
# #
# fact [letter] = [true/false] : set the fact statement (not saved !) #
# save : save the new facts and reevaluate the rules #
# query [letters] : print the fact(s) corresponding #
# #
# rules : print all rules #
# facts : print all saved facts #
# facts:statement : print all facts statements #
# reset : reset all facts and rules #
# quit : exit the program #
# #
=======================================================================================