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importracketdatalog

Import a Datalog knowledge base in Racket

Is it possible in Datalog Racket to import and use a knowledge base defined in a file x declared as "#lang datalog" into another file y declared as "#lang racket"?

ex:

;; x.rkt

#lang datalog

parent(john, douglas).


;; y.rkt

#lang racket

(require datalog)

(require "x.rkt")

;;(datalog parent (? (X douglas)))  DOES NOT WORK
Solution

  • The exported theory from #lang datalog is always named theory, so your y.rkt should be:

    #lang racket

(require datalog
         "x.rkt")

(datalog theory (? (parent X douglas)))

    Note that we are querying the parent table, so we need to specify it as (? (parent X douglas)). (? (X douglas)) is incorrect.

    Lastly, if you wish to rename the exported theory from x.rkt, you can use rename-in:

    #lang racket

(require datalog
         (rename-in "x.rkt" [theory my-thy]))

(datalog my-thy (? (parent X douglas)))