package datalog

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package datalog
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type t

A database is a repository for Datalog clauses.

type interpreter = T.t -> C.t list

Interpreted predicate. It takes terms which have a given symbol as head, and return a list of (safe) clauses that have the same symbol as head, and should unify with the query term.

val create : ?parent:t -> unit -> t
val copy : t -> t
val clear : t -> unit
val add_fact : t -> T.t -> unit
val add_facts : t -> T.t list -> unit
val add_clause : t -> C.t -> unit
val add_clauses : t -> C.t list -> unit
val interpret : ?help:string -> t -> const -> interpreter -> unit

Add an interpreter for the given constant. Goals that start with this constant will be given to all registered interpreters, all of which can add new clauses. The returned clauses must have the constant as head symbol.

val interpret_list : t -> (const * string * interpreter) list -> unit

Add several interpreters, with their documentation

val is_interpreted : t -> const -> bool

Is the constant interpreted by some OCaml code?

val add_builtin : t -> Const.t -> BuiltinFun.t -> unit

Add a builtin fun

val builtin_funs : t -> BuiltinFun.map
val eval : t -> T.t -> T.t

Evaluate the given term at root

val help : t -> string list

Help messages for interpreted predicates

val num_facts : t -> int
val num_clauses : t -> int
val size : t -> int
val find_facts : ?oc:bool -> t -> scope -> T.t -> scope -> (T.t -> Subst.t -> unit) -> unit

find facts unifying with the given term, and give them along with the unifier, to the callback

val find_clauses_head : ?oc:bool -> t -> scope -> T.t -> scope -> (C.t -> Subst.t -> unit) -> unit

find clauses whose head unifies with the given term, and give them along with the unifier, to the callback

val find_interpretation : ?oc:bool -> t -> scope -> T.t -> scope -> (C.t -> Subst.t -> unit) -> unit

Given an interpreted goal, try all interpreters on it, and match the query against their heads. Returns clauses whose head unifies with the goal, along with the substitution.