from_file name parses a file that contains zero or more rule specifications. Returns
Ok rules if all rules specifications were well-formed, otherwise returns
Error e with a detailed description of an error and a location of a subterm that is not part of the grammar.
val of_string : string -> t
of_string s parses the rule specification
s is a well-formed rule specification.
val spec : t -> string
spec rule is the human readable and machine parseable well-formed rule specification.
apply rule fact applies
fact and produces a new rule that contains a partial mathcing state, as well as a list (possibly empty) of newly produced facts.